best way to start writing down/ composing music?

so basically i have a few songs that i wrote out, with bass, drums, the melody and so on. i have a few issues, such as where am i supposed to make music? i heard of cakewalk but it looks a bit difficult. i cant really pay for anything rn but ill think about it when im able to. i also dont know how to put down the notes and im worried it might sound bad or so, the demos i have sound good but im worried i wont have the skill to show that when i write it down