You should not be doing anything that uses the chest muscles in any meaningful way for four weeks. They will put pressure on the (hopefully) healing sternum, and can cause it to separate again, to misalign the wires, or just fail to heal. After that, start up slowly. If you're older or your healing seems to be moving slowly, make that six weeks.
Things that use your chest in a bad way for sternum healing have been listed many times before, but here are some:
Sweeping, vacuuming, or mopping floors
Washing dishes
Scrubbing surfaces
Cleaning tubs, showers, or toilets
Making beds
Mowing the lawn
Bending over to pick things up
Lifting children, laundry, groceries
Doing laundry in a washing machine or dryer
Ironing
Push-ups and similar exercises
Weight training, even with small weights
Hanging clothes
Snaking drains (don't ask how I know this)
Driving (esp. standard shift)
Opening heavy doors
Using tools, such as wrenches, hammers, and saws (including power tools)
Brushing pets' or children's hair
Walking unruly, large dogs
There are many more things.
As an added bonus, anyone who feels the limitations don't apply to them will usually be visited by the Pain Fairy, who is most generous with her gifts.
Please take care of your sternum until it heals completely.
Best wishes,