Add a Rum and Monkey User!
First, make sure that the person hasn't already been added, or you'll get an error. You can view a list of users here. Blue names lead to the profile of the user on this site. Golly this is complicated.
If you are unsure of what the user numbers are, then take a look at this image. Note the position of the big red arrow. It points to the user number. Please enter that number, and not the user number for this site. Thanks.