Stephem, at this point I'd suggest that you download OCPN and start reading the inbuilt manual. It is very complete (albeit a bit disorganized) and will answer questions as they arise.
Doing this for yourself will add to your knowledge directly instead of filtering it through unknown folks (like me) who may not have things exactly right.
OCPN runs in whatever computer you have for it. Getting the input data is up to you -- I use a wi-fi link from a Vesper AIS
unit which acts as a hub for various instruments plus it's own GPS
. Works well. Before I installed that AIS I used a USB link to a stand alone GPS
. There are many possible methods, and all is explained in the manual.