To make it back "Register" button you have to
1) In Module Manager find this module "mod_gk_register" , it should be on "register" postion
2) Enable/Publish it (pol. włącz go)
mod_gk_register.png
3) If you don't have it on list of disabled modules, in Module Manager you should use icon [NEW] to add it.
4) If you don't have installed - you will find him in "gk_twn2_rest_files_J!17.zip" package , unzip it and install separately.