New to owning an aquarium

I was wondering what these green wavey things were on the side , I thought it was from normal aging. But I also want the best for my fish . I’ve had the tank only a few weeks and gonna do my first water change this upcoming week. How can I better keep my tank , what is to be expected in terms of a normal aging tank. I have the conditioner and bacteria for water changes. Please help .

I was wondering what these green wavey things were on the side , I thought it was from normal aging. But I also want the best for my fish . I’ve had the tank only a few weeks and gonna do my first water change this upcoming week. How can I better keep my tank , what is to be expected in terms of a normal aging tank. I have the conditioner and bacteria for water changes. Please help .