They fit under the lip of the bath tub, there may be blocks of wood or a strip of wood to screw them to. Fit them the other way around as shown in the first picture.
Think I had the same one, will you cut the height of the panel? the clips are adjustable (length ways) so the panel can protrude out. If so the bottom edge will require something to support to and fix into as well. You can use the panel as a template to cut the curve from a piece of timber, use a level and plumb down and fix the wooden batten on the floor, you can then use stainless screws accompanied with white headed caps to hide the fixing about4 fixings along the bottom.
They look like they should be fixed to the floor, so that a lip at the base of the panel can be clipped into them, keeping the shape required. Mr. HandyAndy - Really
If it's a P shaped bath you need to set the bath at panel height,then secure the clips to the floor and the wooden edge under the bath,it's a bit fidderly and then clip bath panel in place,HORRAY!! job done. Now every time some knocks the panel in the wrong place it will come lose,its great fun. ENJOY!!!!!