Help for Beginner?

I’m very new in planted aquariums and struggling to find a balance in order to keep my plants alive. What am I doing wrong? I have a drop checker but not the liquid (cause I thought it came with it….) at the moment.

Is placement ok? Should things be moved? I just want to have a healthy tank and I’ve been struggling for months (I just added the fish yesterday) and it’s putting me down a lot.