First of, make sure your plane is in the correct landing configuration.
Speed brake out
Gear down
Flaps down
DLC out
All these things change the pitch of the aircraft, otherwise known as ANGLE OF ATTACK or AOA for short. Once that's all done, you want to get the AOA at the correct angle for landing. Which is 15 units of AOA. This is where the yellow donut comes in. When the aircraft is configured for landing, and the AOA is correctly set on the yellow donut, you are "ON SPEED". When that is achieved, you can adjust your glideslope simply by adjusting throttle. Less power makes you descend faster, more power less fast, and if you give it enough power you can fly level or even climb. All you have to do is set the Flight Path Vector (the circle with the 3 lines sticking out) on the runway, and adjust power to make a smooth landing.
DLC helps with that too, but that's more for carrier landings where a more precise touchdown is needed. For now stick to runways.