@Himali1
Ther is no setting for minimum amount of guests.
But a listing shows up in the search system for every amount of guest up to the maximum.
You own 3 listings, i assume you refer to the "Kandy luxury villa" (10 guests maximum)
It shows up in the search system for 1 to 10 guests.
The screenshot is an example for a search for 4 guests:

If you want to attract smaller groups, you could also consider to set a basic price for a smaller group and set an extra fee for additional guests, more info:
https://www.airbnb.com/help/article/1507