You'll want to start as many Social Links as you can in April of Persona 3 Reload. Doing this will make it easier to unlock more Social Links later in your playthrough. Mamoru Hayase serves as the Star Social Link in Persona 3 Reload, just as he was in the original Persona 3 and the male protagonist route in Persona 3 Portable. To start Hayase's Social Link, you'll need to have started the Chariot Social Link and have high Academics. Fortunately, this Social Link unlocks around the midpoint of Persona 3 Reload, so you should have plenty of time to prepare until then.