Firewall config with home network

I have two machines, one XP home edition with Kerio firewall 4 and the other windows 98SE with Kerio firewall 2.0 and I finally got them to see each other on the network. Concerned that I may have allowed more than just computers in though. On XP machine, I added ip/mask into trusted area and allowed for Microsoft Printer and file sharing to be allowed in/out(internet) and in/out(trusted). Should I have done that? I am not sure if internet should ever be permitted in for file sharing. On 98SE machine, firewall asks for protocol which included UDP, TCP, TCP and UDP, ICMP, and other. Can anyone tell me as well which of these should be utilized and whether it should be incoming/outgoing? Just want to be sure that I will not put myself in harm’s way.