Upon unlocking perks, you’ll be given three perk slots. You might slot in three perks and think ‘job done’. It’s not. You need to obtain additional perk slots first. You can purchase one from Zee’s store in Pyloon’s Saloon for 10 Datadiscs, while another six need to be tracked down. That’s a total of ten slots, and you’ll need to find Essence points to acquire them.

When you’ve completed all seven Jedi Chambers, travel to the Alignment Control Center (you’ll unlock this Meditation Point towards the end of the story), and use BD-1 to slice the terminal, checking that all seven monitors have turned green. This will enable you to locate the Essence locations required to unlock the remaining Perk slots. Slot enough Perks at a Meditation Point to fill all ten slots once you’ve acquired all ten, and this will unlock.