Fitting on Fibre Cement Slates

[JBF]

Hi There, I am just about to do my first install on a slate roof, yes I know I am lucky not to have one before. Have ordered K2 slate hooks to do the job and it is on a new roof that is going on at the same time so makes it easier I know. I presume from looking at them that the slate hooks go flat against the rafter under the battens and just come up stright through a cut in the slates to be flashed in. Any advise on this gratefully received as don't want to muck up the first one of these!

Thanks in anticipation