I see, some old dot matrix labels. Well, I think you'll just have to experiment. I think you might be able to use them by adjusting your printer paper feed guides to a certain position, especially the left one, and aligning your label sheets next to the left guide. I imagine the best technique would be to separate/tear the label sheets into sets of two, i.e. two 6 inch sheets, rather than trying to run them as continue feed.
And, you'll probably need to experiment with printer settings in the software you use to print labels. Again, I think all you can do is experiment with this to see if you can get it to work.