Hello @Jami2626
There has been a lot of talk on the CC about this subject and it seems that hosts who opted in for the new version of Airbnb lost their original settings. You can make a search above in the search window but it would seem that they only way to set different minimum stays is to opt into "the professional tools".
This feature is now available to all hosts not just those with multiple listings. I think it's a great feature and I have several different length stays programmed for my listing. A new "multi-calendar" appears and this one is linear and from there you can "create new rule sets" which allows you to set different length of stays, promotions, set arrival and departure days.
Here is a link to an earlier conversation on the CC but there are many others too:
https://community.withairbnb.com/t5/Ask-about-your-listing/Custom-Trip-Length-issues-since-new-updat...
All the best
Joëlle