How to swap hotbars?
Medieval Engineers allows you to have multiple hotbars, in order to group your weapons on 1st, your house structures on 2nd, etc.
How to swap from the 1st to the 2nd, and back to the 1st?
In a https://steamcommunity.com/app/333950/discussions/0/618453594741953930/#c618453594741960122 , a user posted that you use Shift + 1 through 4 to change between them:
Press Shift+1-4 to view the different hotbars
It now seems to be Ctrl instead of Shift according to https://gaming.stackexchange.com/questions/398834/how-to-swap-hotbars/398852?noredirect=1#comment560473_398852 .