I got it running fine hardcoding the parameters into the Query field:

Not a fan of query string parameters, anyway.   Now, since one of those is the UserId, how can I pass its token to the SP?  I read that they are available but not how to add them to the call.  Thanks.

As Sebastian said, in the "Allowed URL Parameters" field, just enter your parameter name without the url_ part, like this,

member,reportuserid

Make sure there are no spaces, just commas in between.

The UserID parameter is different. If you want to pass the current user from the report page to the stored procedure you do not need to enter anything for it in your "Allowed Url Parameters" Notice in my example above there is no mention of the UserID. You will pass the UserID in the procedure call later. See below.

Almost there. Now when you enter the query or stored procedure you reference each of your parameters with the name you entered above, preceeded with url_
Like this,

EXEC PVAS_UserRoster url_member, @UserID, url_reportuserid (spaces are OK after the commas this time if you wish)

Notice that the UserID was passed by simply including @UserID in the procedure call in the right order.

That should do it.

Also, just an additional note. The UserID is stored as an int data type, not a varchar.