Arranging the song by yourself

An extra hint to pick the right key

When the original song sounds neutral for example "Me" from Breakfast with Amy. I pick the C-key.When the song is cheerfull, I pick the key E. When the song songs sounds between neutral and cheerful, I choose A

How do know Where to put the chords in the song?

There are some basic rules: Of course this is music, (especially alternative-rock does not always follow the standard musical rules), you can also use another chord to start or to end then the Key-chord. But for beginners and intermediate musicians I would advise, follow the rules, only when it really does not sound in your cover, go for an alternative.

The second instrument

Remember every key has also a different scale: When you use a bass instrument or a solo instrument, use the right scale if you want to follow the proper musical rules:
If you are not familiar with this theory, you can look it up in the guitar course by Will Schmid from Hal Leonard.