A casting reel is set using the line spools shaft bearing nut, which is opposite the star drag.
What you do is tie on the weight and whatever bait you're using that day.
You hold the rod straight out at shoulder level and engage lever or button spool release.
You keep tightening the spool shaft bearing nut until the line spool stops rotating when the bait hits the ground.
So when you cast out over the river, the spool slows down to a halt when the bait hits the water.
That keeps you from having a snarled up backlash.
You are using a casting reel to troll with.
What you do is tie on the weight and whatever bait you're using that day.
You hold the rod straight out at shoulder level and engage lever or button spool release.
You keep tightening the spool shaft bearing nut until the line spool stops rotating when the bait hits the ground.
So when you cast out over the river, the spool slows down to a halt when the bait hits the water.
That keeps you from having a snarled up backlash.
You are using a casting reel to troll with.