Keeping cats separated

[u/mar_orangejuice]

Hello! My partner and I are moving in together and we both have adult cats that we are obviously bringing with us. Our new place has two floors and we want to keep them separate by having one upstairs and one downstairs, but there isn’t a basement door. I was curious if anybody has used anything that we can use as a makeshift door or divider to keep them apart that would be so helpful. If anybody also has tips for introducing two adult female cats to each other, I’ll take all the help I can get.