Ok we all weren’t new to the hobby at some point.
I first suggest you go and read the thread about the nitrogen cycle as understanding that will help you to understand water parameters and why we check for them. I’ll see if I can find it and repost the link here for you.
Now as for water testing - you should go and get an API Freshwater Master Test kit. This is a crucial tool to have especially when starting out in the hobby.
Do you do tank maintenance such as weekly water changes and which water conditioner do you use ?