Windows 11 Replace characters in a file name with other characters

I have a large library of music file names (mp3 files) that I need to change to conform to certain criteria.

1. I need to append the two digits "00" to the beginning of certain filenames that do not have a track number
2. I need to replace the two characters "(a space)-", that may appear several times in different places, with a comma ","
3. I need to replace the first two digits (say 09 for instance) in certain file names (digits vary from file to file) with "09(space)-" (i.e I am effectively adding a space and a "-" after the track number

I have seen many examples where get-childitem is used in similar circumstances but I get lost with the bit at the end, that between the {}

So far it seems that I need to use - get-childitem -recurse | rename-item rename {???????????}

I am an experience user of Windows computers and OK with the use of the command line operations. However this command seems so complex and baffles me