Communion?

OK I'm trying not to ask so many questions but I can't help myself.

Was communion part of the old laws or is it something that Jesus started at the last supper? Is it necessary?

Jesus Started it at the Last Supper. It is identifying with the Body of Christ (basically), which had not existed on earth in physical form prior to Jesus. Some of the more learned or verbose may offer a longer explanation, but I think that answers the basics of your question, lol...Oh yeah, and yes, Jesus said to do it often in remembrance of Him

Does it have to include footwashing? How often is it generally done?

It is not normally done with footwashing. Only a few churches actually do the footwashing anymore. It varies in frequency from church to church from as often as weekly to quarterly. My church does it at least monthly, sometimes more frequently, and at special occasions as well.