Plug in the ethernet cable or connect to the wifi at the screen when it is required.
Disconnect the ethernet cable or turn off the router/wifi
At the screen where you are asked for Microsoft account Hold down Shift and press F10
At the command prompt that opens type OOBE\BYPASSNRO
Computer will restart and you will be able to enter a local account name.
UPDATE
With chnages to Windows 11 the above might not work. if that is the case put in the username of a@a.com and the password of whatever you want at the Micorsoft account log in screen.