Quality sessions, with ample rest between them, don't train sore muscles. Fuel your body, plenty of protein throughout the day to build muscle tissue. Keep a log and keep your sessions regular.
Consistency is the key.
Session 2 should be performed on a totally different day, ideally two days after session 1. The weights that you use, should reflect on your current strength levels, for safety reasons, start with a lightweight establishing good technique before increasing gradually. Flat bench press, using either machine or free weights. Pec Deck on either machine or dumbbells, reduce the weight each time, maintaining correct form. Bench Flys on either inclined or flat bench, using dumbbells.