I am installing a domsjo sink from ikea. It has a felt ring with the drain do I also use putty with it?

Yes, putty goes on the drain before you drop it in place. The felt ring goes on from under the sink so it touches the underside of the sink. Then install the cup like spacer and nut. The putty should goosh out as you tighten. Scrap the excess of with a plastic or wooden scrapper. How To Install An Ikea Domsjo Farmhouse Sink - YouTube should help with the carpentry aspect of the install but Kitchen Sink Basket strainer install. - YouTube will help with the drain.

Boy! Have I got a video for you, A complete installation guide for your new sink. To view, click on: How To Install An Ikea Domsjo Farmhouse Sink - YouTube
Good luck, Tom

Im pretty sure I just watched the same video twice. Lol. Great minds think alike for sure.