Which bodybuilding exercises should beginners do?

Build a great base. Bodybuilding can be a fun pursuit, and lean body mass is an important feature of optimal health. Your first "lifts" can exclude any plates, dumbells or machines. Build a strong base by establishing core strength and breathing technique. Planks, birddogs, wall squats, split squats, push ups, crunches and leglifts are just a few. Core strength will support proper technique and great results.
Start slow . The biggest issue weightlifters / bodybuilders get into is shoulder injuries from lifting too heavy weight before the shoulder cuff is strong enough. Start with relatively light weights and high repetitions and please include exercises to strengthen rotator cuff muscles. Avoiding injuries is the key to long term success. Enjoy!