i just knew straight up, thats probably not helpful but idk. sometimes others perspective can help give you perspective ive learned, so ill tell my experience. though i think having the thought of wanting to find what will make you happy, is a great first step to finding it
but yeah i just knew, i truly feel like it was destiny. my mom and dad were both really musical, when i was a little kid my mom had me take piano lessons just cause she did growing up basically. they both had a lot of knowledge and i was always listening to music, my mom was like a really popular singer locally, mostly like in the church choir and her school choir. then she went to music school and i remember being taken to all sorts of orchestra and opera concerts as a kid. i was always exposed to different types of music and pushed to embrace music
it wasnt till i saw my friend in high school bring his guitar to school, he was playing stairway to heaven and i thought it was so cool. but i also thought, yeah i could do that. and it was like a domino effect, i remember that weekend my uncle called me and said he wanted to fund me doing some sort of activity randomly i thought about the guitar but ignored it. then i turned on the tv and the George Lopez show was on. it was like an episode where his son wanted to learn to play guitar and the whole episode was about guitar playing basically, so i took that as a sign and called my uncle, which he flew down and gave me his guitar. i was just a natural and got good really fast, fell in love, played it for hours and hours everyday, basically when i got home from school i played all day till i went to sleep. i would sing all the time to songs i liked all my life before then, my mom and sister told me i had a beautiful voice but it was kind of high for a dude, always was. i remember i was singing one night to a song and i felt my adams apple drop and suddenly i had a lot of range and could hit lower and higher notes. i started wanting to sing with the guitar and i remember i posted a video singing Where did you sleep last night by Nirvana on facebook. and it went kind of viral, so then on i knew what i wanted to do forever and went after it for like 7 or 8 years, eventually getting to a point where i wouldnt settle for anything else. then i made a song that blew the **** up and now i am music
so yeah thats basically the short version. you just know but it my case it was put infront of me all my life, could be the same for you or not idk. but when you find it youll know