To get support for the modpack, please open a new issue in the official GitHub repository.
DO NOT post any bug/question/suggestion in the modpack's page in the platform; DO post them in a new issue in the link.
Type in the modpack name (The 1.12.2 Pack) or paste the following url into the search box.
Finally, click Install at the bottom right of the launcher after you select The 1.12.2 Pack from the list on the left. The launcher will handle everything else!