For the life of me I cannot understand the recommendation of leg press, chest press, and shoulder press. The leg press makes sense, since it works most of your lower body. The chest press will work your chest, shoulders, and the back of your arms. But I cannot for the life of me understand why someone would recommend a shoulder press if they only mentioned 3 exercises. A better exercise would be a row. A row works your upper back (primarily the lats), and the front of your arms. By substituting a row instead of a shoulder press you are working a lot more muscle. If you are only going to do a few weight lifting moves, I would suggest sticking to ones that work a lot of muscle rather than ones that just work a little bit. Some good exercises to include:

Legs/Butt;
Leg presses
Squats
Step-ups
Deadlifts

Upper Body;
Bench Press
Chest Press (usually refers to a machine version of a Bench Press)
Row
Lat Pull-downs
Pullovers

You may also want to do some ab/lower back work to maintain strength in your core. It sounds like you have access to a gym, so you should be able to find someone to show you these various exercises.

Brett