There could be a couple of things causing you to have problems on landing.

First of all, check the CG. If you are "on the edge" of your CG, you might want to add an ounce or two to the nose to help get the nose down.

Second, prop choice is always a consideration because to high a pitch will make it fly faster, but will also set you up for landing faster. You might want to drop down in pitch a step at a time.

Third, your approach may be to short. If you lengthen it somewhat, you will find that your plane will have time to slow down to landing speed. Fly the plane. When landing, set up your approach so that you never see the bottom of the wing. That teeter-totter point where you see it then you don't.. then work on the approach so that you just don't see it but are not to steep because you will gain airspeed then the flair maneuver will cause you to balloon back up and start that porpoise action (up then down then up then down).

And a combination of all three is what's most likely happening if you are a newbee. It takes time and practice. Do a lot of approaches without actually landing the aircraft. Come around and set up the approach. Come in as though you intended to land, then when happy, slowly push to full throttle and go around and do it again.

Sooner or later, you will find yourself doing the right thing with the throttle in the downwind leg, then turning to base, again with the right throttle setting, then on final where you want to be and at the right rate of descent. Do it over and over agian until you don't have to force yourself to think about it, it will come automatically with each approach, based on the wind for that day.

Best of luck.

CGr.