How did Luke find his students?

The dozen students he was training with Kylo. How did he locate them in the first place?

I'm assuming he was able to sense them in the force, but I wasn't sure if it had been mentioned anywhere?

Well Luke also found Jocasta's "School of the Force" at some point, which contained an abundance of Jedi holocrons and texts.

...I'd assume acquiring such a vast plethora of information helped him find students as well. /shrug

Well, I know this is kind of stretchy, but the ending to "Yoda: secret war" was left fairly openended, so maybe garro showed him something. I mean, garro did manage to locate Obi-Wan, so it's possible he has some ability to find other jedi.