Perhaps a couple… first is the order. I did shock tower, wheel wells, and lastly that back panel. Turned out well because each section covers the pervious. When I first test fit them I thought I was screwed but once you actually glue them down, they take shape.
I used 3M spray on adhesive. That worked well. Spray both surfaces, let them tack up and install.
For the shocks, start at the top and line up the lip that goes around the rounded section and then just pull the rest down and try to stretch the material as much as it will go without creating creases. I had to make some relief cuts at the bottom but they won’t be seen since they will be under the carpet. You may need relief cuts on the wheel wells too. I have some but they won’t be visible. Make sure to line everything up and you’re happy with the figment before making any cuts.
I found it useful to have my seatbelts and seatbelt covers close by since they mount onto my shock tower. This gave me a good visual to compare from side to side as far as equal alignment on the shock tower.
Lastly, the glue isn’t permanent so don’t be worried about pulling a panel off after it’s installed… I did my passenger shock tower about 3 times until I was happy with it. And I might redo my driver too.
Hope that helps…