I haven't seen this design before today. So I thought they should be shared becuase it is a very nice design. You need to pop out the original mounts from the subframe...they can be damaged during removal. These new mounts slide into the subframe from above and below without it having been removed. You align their notches to the dogbone before tightening the three bolts included. They have a lip on their outer edges to hold it in place and together in the subframe. The large center bolt is likely put loosely into place.
https://www.akstuning.co.uk/shop/ho..._bolts/1129-vibra_subframe_insert_listing-yes
https://www.akstuning.co.uk/shop/ho..._bolts/1129-vibra_subframe_insert_listing-yes