Adjust how long of a draw your throw takes by changing how fast or slow you do it. It’s not a yoyo; you don’t throw it necessarily fast.
As you throw the top at varying speeds, note how far down the string the top is when the tip is pointing down. When you throw for a boomerang, you want to start pulling it back towards your hand slightly before this point. When you throw for the ground, you can throw a little slower so that the tip is pointing down right when it is at the end of the string.
It’s all finesse and practice.