New them installed Homepge block is not shown, only Home page for luma is available. How shall I change the homepage now? I tried creating new homepage and linked it Store >> General >> Web >> Default page >> CMS Home Page. But it did not work.
Follow the bellow steps to for your theme:-
Step 1) Install your theme module First.
Step 2) In Content->Design-> configuration, Assign your theme according to your store.
Step 3) Store -> General -> Web -> Default page -> Your Theme CMS Home Page
Clear cache and check.
Still, you don't get you blocks on the home page then check theme blocks are imported/Enable in the backend.