What is a USB network link (bridge)? I bought one, but when connecting two laptops they still cannot see each other. How can I do this?
Your question is very vague.
There are two different things I can think of two different solutions from what you wrote, and not sure which one is accurate.
If you purchased a USB <-> USB cable, you will need to use special software to transfer files under most circumstances. For example, if this is a Windows machine, use Windows Easy Trasnfer.
If you purchased 2x USB <-> Ethernet converters and an ethernet cable, you will need to use a cross over cable (unless you have automatic sensing adapters), or a switch and then set up networking in a normal way (easiest way is to use the wizard).