Hello,

There are many ways you can approach this. As far as "Courses", there are music colleges and some times local commuity colleges might feature songwriting courses. But personally, I'd avoid those, at least for a while untill you get some experience. There are a number of ways you can do that.

#1. WRITE.
You should be writing lyrics, studying hit songs, learning about the craft in any way you can. Most about writing is like a NIKE COMMERICAL.
"JUST DO IT!" There is nothing keeping you from writing your poems, your stories, your scenarios, and learning as much as you can by doing.

#2. YOU TUBE.
There are millions of videos on all things entertainment. Do a search for "SONGWRITING TIPS" and you'll get enough information to last you a few months to go through. Everything from hit writers and celebrities talking about their lives and craft, to new comers, to even teachers and coaches who do this professionally. Be careful, you'll probably run into my videos. I've got a lot of them. Having done this for many years, workshops, seminars, etc. I have a lot of things I don't even know about that other people have posted. But there is a lot of people up there and you just need to start digging.

#3. LOOK AT WHERE YOU ARE, AND OTHER SONGWRITING SITES.
Anyone here is a writer at various stages, various experiences. The more questions you ask, the more information you'll get back. You also can contact people privately, check out their music, either here or on web sites. Once again, you'll probably find much more than you ever realized. But I will tell you this, the more you know about music, the more you realize that you DON'T KNOW about music.
Different than the music business. The MORE you know about the MUSIC BUSINESS, the LESS YOU WANT TO KNOW ABOUT THE MUSIC BUSINESS.

#4. SONGWRITER NIGHTS, OPEN MICS, TALENT NIGHT.
Almost every town, hamlet, city, suburb, etc have some form of music nights going on, usually featuring original songwriting. With the advent of all the reality shows, AMERICAN IDOL, THE VOICE, AMERICA/BRITIAN/AUSTRALIA/WHATEVER HAS TALENT" shows the amateur talent nights are EVERYWHERE! Invaribly, those people are out doing much the same thing.
Writing songs, recording them, performing them, etc. About 100,000 music videos, songs, cell phone videos, etc. are uploaded an hour to YOU TUBE AND FACEBOOK ALONG. Spotify just announced it had reached 100,000 a day, so they are just catching up. There are literally millions upon millions upon millions "releasing" (very nebulous term) billions of product continuously. So you will keep busy.
But I'd go to these nights. Start some conversations, meet people. Study what they do, but make sure they don't think you are "stealing" their songs. (another nonsensical term) but making some mental notes on what people do right AND wrong help sculpt your own attempts.

#5. CO-WRITE.
All the courses, all the classes, all the workshops, in the world don't take the place of WRITING WITH SOMEONE ELSE. You learn in real time things that work and don't. You learn by doing, and while everyone would love to "just write quality" it doesn't work like that. The ONLY way to "QUALITY IS BY QUANTITY." You have to write a lot, most do it every day. but at least several times a month. And if you have very little experience other than singing, you need as much help from as many directions as you can get. There is nothing like actually doing it.

#6. LOCAL AND REGIONAL SONGWRITERS GROUPS.
Again, most areas have a group, either formal or informal, who get together, share songs, talk about the ups and downs of the weirdest journey any of us will ever be on. They can be very small, just a couple people sitting around a living room playing guitars and singing. They can be a larger get together, with dozens or sometimes hundreds of people, with a professional or semi professional leadership, doing song critiques, having workshops, getting together for a shared interest. They will often do shows, have regular or semi regular open mics or open stages of their own. So if you have your own songs (which you are going to need) you will be able to demonstrate your talent as well. Might even get some demo sessions, which will teach you MORE about songwriting.

#7. PRIVATE COACHING.
There are many people who do this. Again, an Internet search will help you here. I live in Nashville and there are many, including myself, that do long distance coaching for writers. They have various focuses, etc. But you can usually visit web sites, get information, and decide for yourself what you might want to focus on. Usually it is more like you write some things, submit them for critiques, which will give you a basis of framework to learn from. You can do that same thing here, post some songs, get feedback, and see where it goes from there. Remember, like everything, it is OPINION, and everyone is going to have their own perspective they come from. Getting some feedback from a jazz musician on a country song, or getting an opinion on an experimental rock avad guard song from someone who deals primarily in country, may not be on the spot, but all will get you outside of yourself. 
I'm NOT here to promote myself. Anyone that wants to know about me, check out my profile here or contact me privately. 

#8. LISTEN AND LEARN.
With every writer you meet, you will generally meet three more writers. They all have different connections. go to different venues, attend different workshops, perform differently have different expreiences. So you actually can meet quite a few people very quickly. Most will be like yourself, fairly inexperienced, as much of this is a sort of beginners approach. Once you start developing your own contacts, circles, etc. you don't need to weed through the larger things. It all happens fairly organically, so don't worry or be intimidated. The good news and bad news about anything music is pretty much the same:

THE GOOD NEWS IS everyone is JUST LIKE YOU, trying to do the SAME THINGS, UNDERSTAND WHERE YOU COME FROM AND WHAT YOU WANT.
THE BAD NEWS IS    EVERYONE IS JUST LIKE YOU, TRYING TO DO THE SAME THINGS, UNDERSTAND WHERE YOU COME FROM AND WHAT YOU WANT.

It is very competitive and often very confusing. But if you keep a sense of yourself, your interests, and just know that you have to work on it all the time, you will be able to accomplish a lot more than you think you will. None of us may ever "hit the big time" but most will be able to serve our creative soul and spirit, share what we want to do with others. And a lot of times, for most people, that IS THE BIG TIME. 

MAB