I can’t transfer the site to https, the site is written in YII2, below is .htaccess which is at the root. What additional information needs to be added to the file?

Question

htaccess

Options +FollowSymLinks
IndexIgnore */*
RewriteEngine on

# If request starts with /admin, then change to /backend/web/
RewriteCond %{REQUEST_URI} ^/admin
RewriteRule ^admin\/?(.*) /backend/web/$1

# Add another request /frontend/web/$1
RewriteCond %{REQUEST_URI} !^/(frontend/web|backend/web|admin)
RewriteRule (.*) /frontend/web/$1

# If frontend request is
RewriteCond %{REQUEST_URI} ^/ frontend/web
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /frontend/web/index.php

# If backend request
RewriteCond %{REQUEST_URI} ^/backend/web
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /backend/web/index.php

When I add these lines, the site works but styles fall off and JS
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI }

Answer 1

First of all, on the hosting side.
1 Install an SSL certificate (Let's Crypt is free)
2 Set up an automatic redirect to https
All this is done in the hosting control panel