Hi, is it possible to set up several servers on one computer using "BF Server Manager"? If so, how to do it?

For a customer facing configuration you would need a thorough understanding of ip addressing and masking, port configurations, firewall configurations, with suggested additional knowledge of vlans and lan isolation. Include in that is a good knowledge of possibly linux os or windows os, server os preferred, and include in that a true soho router that supports a true dmz. NO port forwarding to the inside network, !EVER! I have servers pounded on by nefarious governments and unscrupulous actors constantly. I would not sugget anyone open a server into the wild without a thorough knowledge of all the points above or you could be opening yourself up to some serious trouble. Just using bf manager isn't enough for a correctly configured secure server setup.