A showing is typically scheduled 24 hours in advance. You let your Realtor know that you'd like to visit Home A, B, C, etc., and he/she will set up the appointments. Your Realtor will also gain access to the homes for you, and he/she can supply you with pertinent information (such as the square footage, the heat source, etc) as you walk through the rooms. Another idea is to see if the home you're interested in has an Open House scheduled. In that case, tell your Realtor that you're planning to visit House X this weekend -- but in that case, you will be "on your own" (unless your Realtor decides to attend the Open House as well).