Underfloor heating mat -tiling

[Paulboy]

I am tiling my floor and putting down a heating mat

Am a bit confused..... as the instructions on the booklet and on here differ.....

The booklet suggests laying tile cement and then laying mat and allowing to dry, then

While other people suggest laying mat then laying mat, cementing and tiling on top

Can anyone confirm the best- most reliable method to get this right?

 

[Paulboy]

Anyone ....

Ive got to lay it on saturday!!