I am 77-years-old where could I find someone to help me with a few chores I am unable to do.

Hire a good housekeeper, slowly expand the duties and pay.

Care.com

As mentioned by AlvaDeer & MG8522 try Caring.com. They have a category called: Companion care for Non-Medical assistance such as cleaning, shopping, errands, etc

You could check on Care.com. (In many places you can have groceries delivered which would be less expensive than paying someone to shop for you.)

You could check with your local Senior Center. They might know of someone or refer you to a person/agency that can help you find someone. Neighbors and friends may have suggestions.

I would call your local council on aging and ask where you might start in looking for handy persons. You might also check the nextdoor app and consider looking at care.com.
Good luck. Unfortunately the old days of bulletin board ads are over. Hard now to find the right place to look.