The first thing you need to decide is WHAT do you want from music
Do you want to be a performing artist - ie performing your own songs and being "discovered"
OR
Do you want to write songs for other people to perform
(these are the 2 VERY broad options that I think face you)
Performing Artist
You are looking to be signed by a record label, who will give you an "advance" to record your album and support your marketing. When you have sold lots (and lots and lots) of records you will have paid back your advance and will start making some money yourself! (after everyone has taken their cut - manager, agents etc.)
Unfortunately it doesn't really work like this any more. Labels are getting much more risk averse so will only take a punt on an artist which virtually guarantees them some success (or rather £$£$£$£$)
So to go down this route you essentially need to do the work of a label yourself - ie build a following, get gigs, get exposure, release an album, get known on social media etc. etc. etc.
You will need to pitch yourself AND your songs to A&R people at labels
The unfortunate truth is that "looks" and image are as important (or actually more important) than your songs/talent
Writing For Others
In this scenario you are looking for a Publisher to take on your song and then for them to pitch it to artists, labels etc. on your behalf
Getting publishers to listen to your songs is as difficult as getting to A&R people and there are lots of companies out there willing to charge you for the privilege - some have less scruples than others!
A good place to start looking is TAXI who have some very good guides and resources - although I would suggest that you don't spend a penny until you have a good collection of "hit potential" songs or you will waste an awful lot of money!!
In either scenario the songs you pitch MUST be very high quality both in terms of the song itself and the production