If it's the same as it used to be. You apply the tanking paste/liquid stuff in the corners and upto your line on your bath, I used to use an old paint brush for it. Then you have a loo-roll sized strip of membrane (I mean about the same width of loo roll, not length) which you apply in the corners and onto your bath. Then paint over it with the goo again, then either roll or paint the goo onto the whole wall.
You'll be able to cut a cross into your netting/matting/loo roll stuff and apply that over your pipes and paint around it. Ensure you have fully tanked to the pipes and onto the wall. Ensure you don't FULLY cover the pipes in the goo as it'll still need to connect into the shower or mixer or whatever.
You'll be left with a fully tanked corner of the room. So if you had a shower at that point with no tiles on yet, ALL the water would run down the drain. So take a step back and have a good look and imagine the shower running and make sure you have tanked everywhere you need to before you tile.
When setting out, use a felt tip rather than a pencil just in case you pierce the tanking should the pencil be a bit too sharp or whatever. And take a bit of care when trowling over it. It's tough stuff, but it's not worth risking scraping the trowel over it.
With some tanking systems you do get a big sheet of the material you'd use in the corners, which you'd then apply to the whole wall sort of thing. I'm pretty sure WP1 doesn't come with that though.
I'm sure there's a youtube video or two on this, I'll go see if I can find something for you.