Dear Yannick @Yannickfischer
The Link you have given does not take me to this domain, ( i think this is a placeholder? )
However i do not think this affects your question:
I do not completely understand, forgive me:
"
Because if I install the laytheme on the maindomain, I won't be able to access on the woocomerce plugin and put some template on a specific page ? "
We have not released Woo-commerce compatibility yet for Lay Theme but are working on it.
Please if you could re-phrase the question sorry! :)
Best wishes
Richard