It's simple. You tie one short piece of tippet to the ring and tie the dropper to that. You than add a long piece of tippet and tie the point fly to that.
I don't find that I tangle any more or less with that set up than just tying the dropper to the tag of the blood knot.
I don't think the OP was talking about dry/"dropper" set ups, rather two nymph or two wet flies. You can still use a tippet ring with a dry, though. Just put the dry at the point position and make the dropper a true dropper.
In all cases, you'll hook a lot more fish on the top fly with either a tippet ring or tying to the blood knot tag than if you tie to the hook bend. Plus, you can use a barbless hook without the tippet slipping off.
The big advantage to the tippet ring comes in the winter, when you can pre-rig the dropper and point at home. When you get to the stream, you only need to tie one knot with cold fingers.