My first FMS, still learning the ins and outs. However, half the time when I try and enter an airway, I don't get the line select next to airways available in the menu. For example, leaving Virginia last weekend, cleared via HIICH2.MCRAY J518 DJB etc etc. MCRAY does not directly connect to J518. In actuality, the closest entry is the IHD VOR. Because I'm relatively new to this kind of flying, is it assumed I'll go direct IHD before entering the airway? My guess is because half the time the waypoint before the airway isn't a valid entry point, that's my problem.