You don't need to enter the needed gridelements manually :) but half automatically.
Add a folder for grid layouts. For example
Create backend layouts (use it only, if your table tx_gridelements_backend_layout is empty!)
replace 'xyz' with the page id of your folder "backend layouts" from above
Copy the SQL statements from the file and paste it into PhpMyAdmin
Send the SQL statements
Create backend layouts icons
Copy the icons to the tx_gridelements folder in uploads:
cp -aR typo3conf/ext/start/Resources/Public/uploads/tx_gridelements/* uploads/tx_gridelements/
Check the content of your folder "backend layouts". It should contain 8 backend layouts.
The needed extension Gridelements 8.x isn't published in the TER currently.
You must download it from the Git-repository at