Pretty simple once you remove the crossover board from the cabinet. I've done a few. What you're looking for is one the many available "5-way" binding posts that accept any kind of connection. You'll find many at Parts-Express.com. I've used these:
https://www.parts-express.com/dayton...ckel--091-1247
They offer an assortment of connect options inside.
The only caveat with the JBL is the depth of the board inside the back baffle. Its about 7/8" deep - so any binding post that sticks out past that will get dinged if the speaker winds up on its back and could break the crossover board or just push the post through it.