Find your Nmbrs subdomain
Add the subdomain for your Nmbrs account to Merge Link.
For example, if you sign in at "merge-test.nmbrs.nl", add merge-test.
Do not enter the full "merge-test.nmbrs.nl".
Find your Nmbrs API key
1.) Sign in to Nmbrs and click your profile icon in the upper-right to show the dropdown menu. Visit User Profile in the menu.
2.) Click API Token in the upper menu.
3.) Copy and paste in Merge Link.