Hi Scott, and welcome to VATSIM! In addition to the suggestion provided by Tomas and as an initial intro to what's expected, you can check out the Pilot Resource Centre on the VATSIM website at
https://www.vatsim.net/pilot-resource-centre. This page covers the basics about flying on the network. You can also log on at an airport with ATC currently online, preferably where there is also some traffic, and just sit on the ramp and listen on frequency to get an idea about what information you should you need to keep available for reference.
There are a few different sites where you can view the Navigation plates/charts for flight planning purposes as well, i.e. Skyvector.com, AirNav.com, vroute.net, just to name a few.
And lastly, sometimes when ATC covering the airport you are at has time available (low traffic volume), they will be glad to offer some assistance when work load permits.
At any rate, glad to have you as a member of the VATSIM family and I hope you find many hours of enjoyment with the hobby.