Hi,
Have you used the clamps which come with the ribber to set the main machine up at an angle? Once you have done this the ribber slots into the ends of the main bed - I take it that you already have the fittings in place at each end. Then you fold down the supports at the back of the ribber and secure them to the table with the clamps which were supplied with the main machine, i.e. the flat ones. The machine and ribber should now be securely joined together and clamped to the table, both at an angle of about 45 degrees to the table.
Hope this helps.
Regards,
Sue
January 2014