Follwoing are steps to show how to check-in in various events at MLH Local Hack Day.
Go to the MLH discord server. Find the "LHD-build-announcements" channel under the "LHD-build jan 10-18" category. A daily message is sent by the organizers consisting of the whole schedule with check-in links. Click on the links and login. Finally, click on register and check-in to earn some points for yourself and your guild.