Please forgive my poor drawing skills. But I've done my best on illustrating this procedure. You'll need a bar weight, swivel, large bead/lil corkie, two duo locks and a kwikfish. When plunking kwikfish, I like using a #40 main line, #20 Lead dropper and #30 leader. My leaders are normally 4-5' and you can experiment with the dropper to get you in the travelling lane. You start by sliding the bead up your line and tying it off to the swivel. Then you can add your dropper and weight.
Cast this out and make sure it anchors itself in the river bed. Then you can tie a leader with two duo locks on each end. Snap the kwikfish on one end and tune it.
Then clip the other duo lock on your main line and make sure you snap the duo lock! Don't ask me how I know this
you drop the kwikfish in the water and the plug will ride itself down to the bottom of the belly in your line. The bead is to kee from losing the rig, and protecting the knot when fighting a fish or reeling in.
I hope you follow the thought process here. If not, feel free to ask any questions. Make sure to tune your plug and Chums will destroy it. The sizes normally used for salmon fishing are K-13 - K-16.