Amphibico Buddy Evo HD 2 right control grip

Hi all, pls can anybody post/sent me howto open the right control grip of Amhibico Dive Buddy Elite 2. The control grip is alredy disconecred from main housing, however I need to replace trigger button since it got stuck. I do not want to break other buttons which are fully functinal. Many thanks for guidance/help, Happy diving! Andy