R.H.
At this age it's not a good idea to have a chore chart yet they are still a little young. What should be happening it when say they are done playing you should be doing instructed clean up. When they are done you go in and say "Put the stuffed animals away", than when they are done you say "Put the cars away" do this until the room is clean. When the older one is about 5yrs old they are old enough for a chore chart. But it should be limited. Maybe put toys away before bed, pick up dirty clothes in room. Small things like that. I have my daughter take the clean clothes out of the washer to put them in the drier for me when i do laundry. She cleans up her toys each evening, picks up dirty laundry that might have made it to the floor while changing clothes. At 6yrs old she is required to "Fix" her bed before school. The best she can there are no strict requirements as far as this just attempt it.
If you require to much too young they will stop helping and it will end up being a fight and it won't undo it's self. Just make sure they CAN do what want them to do.
Good luck