As Jeff said definitely get a good test kit
Test Kits Compared the tf100 is the best value & has great easy to read/follow instructions.
Until it arrives add 5ppm liquid chlorine evey day. It’s hard to find plain household bleach w/o enhancers these days. So look for “chlorinating liquid” “liquid shock “etc.
In the pool section of hardware & Walmart stores. Your pool store may have this as well.
PoolMath will help with calculations you’ll need to input your pool v- the app has a slider for slam level.
Slowly Pour liquid chlorine infront of the jet & brush the area to mix it in
Here’s some reading & info about adding chems
Which should I buy? TFP's recommended pool chemicals are cheap, easy, and won't unbalance your pool water.
www.troublefreepool.com