I'm no expert,but here goes.
On the reel handle side of the reel there should be a round knob. This controls the "tension" on the spool. Tighten it down till the lure [U]slowly[U]unwinds. Try casting with the "tension" tight and your thumb on the spool till the birds nest disappear. Then loosen the "tension" knob a little at a time. The spool should stop unreeling when your lure touches the floor.
There may also be internal brakes. Sorry, those I'm no good at adjusting.