The floor press is your go-to upper body movement if you don't have access to a bench for bench press or you want a simple, but effective exercise to build strength in your pecs and triceps.
You can do this movement with a dumbbell, kettlebells, or barbell. The setup and performance points will essentially be the same no matter what piece of equipment you use.
Start by lying on the floor. If using a bar, position yourself under a rack with the bar at eye-level. Bend your knees and place your feet on the floor. Your upper back and hips should also be in contact with the floor.
Squeeze your shoulder blades together and make sure the glutes stay active when you have the weight locked out over your body. With control, lower the weight towards your chest by pulling the elbows down towards the torso. The triceps should make contact with the floor - think about the elbows being about 45 degrees from the torso.
Once you've made contact with the floor, drive the weight up to full extension through the arms. This is one rep.
It may be helpful to have someone to spot you while you do this movement in case the weight gets too heavy.