Calendar in RealEstateManager built with help PHP.
So, if you want that calendar tab has 3 columns and 4 rows to show the entire year of availability you need edit:
1) functions.php (your website/components/com_realestatemanager)
2) edit style.css usin CSS
3) edit default.php (/your website/components/com_realestatemanager/views/view_house/tmpl)
or hire our developer who can do it for you. For this contact us through our contact form.
It will be faster and easily