Figure bass continuation line documentation

I don't understand how to make a continuation line in Figured bass. I can't interpret this instruction:

"Continuation lines are input by adding an '_' (underscore) at the end of the line. Each digit of a group can have its own continuation line:"

This suggests that to add a figure 6 to a note and add a contiation line do Ctrl G -> 6_
But it doesn't work for me.

If someone can explain it for me I'll update the page if necessary.

https://musescore.org/en/handbook/4/figured-bass#continuation-lines