Here's a link for you Barbara. They also make caps for them, you can check in your local home improvement store.
My dad used to put some under the fold down stairs and remove each time he pulled them down. I am not sure how well that worked for him as he eventually gave it up.
could you use that tape like stuff you buy for sticking around edges of doors? you would have to stay in attic and have someone close the door so you could put the thick tape stuff around the opening tight to the stairway opening edge part.
Here's some information for you: https://www.todayshomeowner.com/video/diy-fold-down-attic-stair-insulation/
On the door tack some insulation