. Any tips on the best way to lay a grass mat, let me know
Unlike Wombat457, I actually use this stuff, and yes, it's a pain, mainly because it's been rolled up and really doesn't want to lay flat again.
The one thing you don't seem to have is glue, I would suggest a PVA or wood glue, (Gorilla Glue) as it works well with grass mats.
Don't as wombat457 suggests, coat both the board and the mat, the mat has a paper backing and it will simply tear.
Using A PVA glue dilute it 70/30 with water, (but it's not an absolute must to do that, just makes it easier to apply).
Brush the adhesive onto about 1/3 of your board and apply the mat, carefully getting rid of any air pockets as you go, you'll need some kind of weights too, anything will do, and repeat the process till it's done, wipe any excess off the sides, let dry for a few hours.
In case your wondering why PVA glue, simply because it lasts for years, and going forward, you will use it.
Hope this helps.