Hi, there! Happy to help.
The main process is to replace your live site’s wp-content folder with the Local site’s wp-content folder, and to also replace the live site’s database with the Local database.
You can connect to SFTP on Flywheel (to access the wp-content folder) with these directions: Flywheel | SFTP Access and Uploads
Once connected, navigate to the wp-content folder, then just drag the wp-content from your Local site into the SFTP client window so that it overwrites the live site’s wp-content.
Then you can head to Database > Adminer in Local, and export the database as a file.
That will download a .sql file to your machine. Next, head to your live site’s Flywheel dashboard, to the Advanced tab, and click into the database manager. Upload the file you just downloaded from Local in the SQL tab of the database manager.
Once that database is uploaded, you’ll probably need to change the database prefix. That’s the set of characters that ALL tables in your database share at the beginning, like in this screenshot:
Note that you SHOULD NOT change the tables themselves. Don’t change their names. Instead, you’ll head to the Advanced tab of the site’s Flywheel dashboard, and change the database prefix from there. (In other words, don’t change what you uploaded; change what WordPress is looking for so that it matches the prefix the tables already have. This will usually begin with “wp” and usually end with an underscore, but it varies.)
Once you’ve done that, you should be in business! Depending on how things were coded on the site you uploaded, you may also need to run a search-and-replace of the site. There are plugins like Better Search Replace to help with that.
If you see the WordPress installation screen when you try to access the site, try turning WP_DEBUG on and off from the Advanced tab of the site’s Flywheel Dashboard. If it’s still there once you do, make sure the database prefix matches up exactly.
Hope that helps! If you get that far and you’re still having troubles, drop us a line here: https://app.getflywheel.com/contact