What you need to do when you move a website?

Hello,

I need to move a web server from one machine to another (Linux servers) and I don't have too much experience in this area.

The problem I'm facing is that I have a server that I don't know too much about it (how it was configured) and I need to get the web site, with the php and sql db from it and drop it in a new machine.

Can someone advise how should I get this web site moved?
Or does someone has a procedure about moving a web site?

Thank you