very basic question regarding zonealarm free

The Trusted vs. Internet columns refer to "zones". With ZA you can define the world of all computers into two primary groups: those that are trusted by you; and all the others, which then fall into the Internet zone.

The idea is that you might have a few computers on your own network that you consider trusted, or perhaps you want to trust your ISP's DNS or Email servers, so, you don't want to have as aggresive a set of firewall rules blocking you from accessing them or them from accessing you. But, at the same time, you may want much tighter rules for all other systems in the world, i.e. those out on the Internet. So, ZA allows you to define your rules differently for Trusted vs. Internet systems.

The "Access" column in the Programs tab is where you: allow(checkmark), block(X) or make ask(?) each program's access out of your PC. If you set a program like Firefox to checkmark under Access for both Trusted and Internet, it means that it can browse out anywhere, to local/trusted systems or any other site on the Internet, without alerting you or asking for permission.

The Server column deals with those programs being able to be connected into by systems out on the trusted network or Internet. If you put checkmarks in the server columns for programs, outside sites can connect into those programs without any blocking or alerting. That's generally not something you want, certainly not for the Internet zone. Although if you P2P, you would need to allow incoming connections to the P2P program for others to connect into your system. That's done by setting a checkmark under Server for the P2P program only.