Welcome to TFP!
Get one of the Recommended Test Kits, I use the TF100 from tftestkits.net.
When you get it give us some test results and get ready to SLAM Your Pool.
Here are some of my fave Pool School articles in case you missed any of them.
TFPC for Beginners
ABC's of Pool Water Chemistry
Here are the Recommended Levels for your pool.
Here is the Water Balance for a saltwater pool.
Here are the Recommended Pool Chemicals and how to add them.
Use PoolMath to figure out how much to add.