Yammyfan
Your question doesn’t seem to make sense. If you want to play in F, you just play in F. That doesn’t require the transpose button. In an earlier post you said you play by ear.
If you want to play from the sheet music you have in Db, but want to pitch it in F i.e. sound as if it’s in F, then you need the transpose function. And you are moving it up 4 semi tones ie 4 in plus direction. Just count the notes from Db to F.
Not sure why you would want to do that though, unless you have someone singing or playing along with you in F. If you are not doing that, and are reading the sheet music you have, why not just play it in Db? There is nothing magic about F. If you want to play from sheet music in F, you have to find different sheet music, the transpose button won’t achieve that.
As I say, I really don’t know from your post what you are trying to do.
And why is someone with enough musical knowledge to identify that a five flat key signature is Db, need to be told how far it is from Db to F……….. that didn’t make sense to me either.
Mike