I've got the oscillating Ridge sander that everybody else has and I've been struggling for a while to connect it to my dust collection.

Previous attempt was just a 6" hose clamped to the side, which worked okay, but was always causing problems.

I'm now moved onto a better approach:

Starting with a 10"x6" HVAC boot from the big box store mounted to the back using a couple of 1"x1/2" sticks. Onto those I added a side flap with magnets, and the another small piece of plywood over the top, which slots into the side flap, and also into a small groove on the right hand side. Improves dust collection about 100x, and I can remove almost all of it to use the round bits on either end, replace the paper, or change to the spindle.

Material total $10 for the boot, the rest made of scrap.