The Count action will return an integer variable called NumberOfUserRoles, it will be e.g. 0, 1, 2, 5 etc.
The Decision needs to return a boolean (true or false)
So the expression you need to formulate has to return a true or a false, an comparison can do that for example:
These are just examples and the first one, might be answer you were looking for. Now the decision will have two outgoing paths (true or false)