How to install theme on mulitistore
Please follow step by step below:
1) Go to STORES -> All Store then create a new store view
2) Go to CONTENT -> Pages then create a new cms page, make sure it's layout is 1 column, not empty
3) Go to STORES -> Configuration -> Web [ General ] then select store view you want: https://prnt.sc/vo4q0 then click "Default Pages" and assign a cms page as homepage of new store
4) Go to MGS -> Page Builder Setting then select store view you want to import a new homepage ( https://prnt.sc/vo4q0i ) then click Import & Export tab then import homepage you want to new store
5) Clear magento2 cache