Never give up! you just spent 4 hours. Leave it a few days, and try again. You will get it once you are rested and relaxed.
Bare in mind th actual clamping is done by the top plate and the chassis. The transmission needs to be able to sit in the cutouts on top and bottom.
Any imperfection in the tranny case or the chassis plates will not allow this. Try bolting it up without the 4 guides to make sure it sits in the correct place, and to better help you understand where everything goes.
Then try one side. Remove the two right hand bolts.
place the lower guide first and insert the rearmost bolt half way in, then insert the top guide, it will be a tight fit perhaps loosening the other two bolts half a tuen will give you enough wiggle room.
Once you have inserted the top guide push the rest of the bolt in and put the washer and nut on, snug down and put in the forward most bolt.
Tighten both down and loosen of half a turn.
Now do the same with the left had side.
It may seem hard but take comfort in that the original car had 8 screws plus thick washers under the bumper wich made it way fiddlier
