I recommend practicing with a C152 or C172 at first.
To keep the plane at a constant speed, practice keeping the pitch constant.
If you’re flying in VFR, practice flying without changing the distance between the horizon and the dashboard.
When turning, do not change the distance between the horizon in front of you and the dashboard.
Adjust the altitude with the throttle.
Without moving the control stick, increasing the throttle will cause you to climb and decreasing the throttle will cause you to descend.