[Typo3] Main html template selector

[Pierre Rouwens]

Hi T3ers,

I need some advise, i'm using T3 3.8.1 and need to make possible to 
choose wich main html template tue user wanna use when create a page.
I've tried rlmp_tmplselector, it works fine but i can't use 
subparts.content < styles.content.get ...
I don't wanna use the possibility to choose a sub template... what can i 
do i've read the documentation but don't fond a way to achieve this... i 
can make a sub template and use it by default it's ok for the customer 
but i don't know what it must exactly contains ??
Any hints please

Pierre