Purchased the Oatey PVC liner after installing my pre-pitch and letting it cure.

I can get the liner in ok, fold each corner in the back of the shower, just having trouble making cuts where it comes to the curb area.

I've read john bridge's site, ontario tiles site, floorelf, etc and they all seem to gloss over this step - maybe I'm over thinking it?

Gave it a go today and ended up making a stupid cut which ruined the whole liner - going to go buy more liner tomorrow - how do I cut it for the curb?

Any help would be greatly appreciated.