Good advice but not always necessary, I've been riding clipless pedals since the mid 80's, never been to a bike shop for mounting and cleat alignment and have never had knee problems from cycling. I always mount my cleats in a neutral position and make small adjustments from there. Still not a bad idea to have a shop set you up though. Most clipless pedals now a days have some float to them so your foot can move around if it needs to, which really helps with cleats that may not be perfectly aligned to your riding style.