This is a classic problem: coming in as a new tester on a system that you are unfamiliar with.
I enjoy it. Clicking around, exploring the features, trying to figure out how they are supposed to be used. Sometimes I’m amazed of how clever an implementation is and sometimes frighten by the poor usability.
But the hard part is not knowing which things are bugs and which are features. I’m constantely popping in in the developer room (why am I not seated with them?) asking “Hey, is this a bug or a feature?”. But my philosophy is that if I encounter something that might be a bit fishy, I better report it than let it be.
However, I’m concerned that reporting all of these things will make me seem annoying to the developers. Maybe they see me as complaining about their design and their work. I do my best to report possible bugs without putting any judgement in them. I hope that helps.