learning my piano and trying some very basic improvisation and I found a chord progression: F-Bb-Dm-D# and I have several questions:
1) I want to develop some melody on top of it, but I struggle to find the key I am in. Which one is it? How to approach this with piano, is there a trick I can use? I know just very basic of music theory and usually "from paper". It's hard to apply it on piano for me. Tried the finder from this site but don't understand it.
2) Is D# correct name or should I say Eb? I guess this can be implied from the key which I don't know.
3) How can I develop a chord progression into song? I would like to create something more complex. I tried to replace D# with C and it seems to be resolving a bit, but there must be something better. Maybe the key and little bit of more theory could help me? So far it was just trial and error behind the piano for me.