Years ago when I was a counselor we called all our families the weekend before camp. I bet you will get an email but they will need a backpack with a lunch, swim stuff, water bottle, sun screen (although you are to put it on before camp) and I suggest an extra outfit in a plastic bag (I pick a light weight set)

Yes you'll get an email and likely a call the week before.

Parents who registered their kids for Camp TO, do you get an email prior camp starting? Or don’t just show up with my kid? 

Asking because I don’t know what I should pack for them and the only correspondence I received was my receipt.

Camp TO question.