There is a little debate about what is the best reading order, but this should help you navigate things after GL Rebirth, if you’re sticking to what’s in this sale that was written by Johns:

Secret Origin came out after Rebirth, but some like it as a sort of prequel to Rebirth.  It gets into Hal Jordan’s backstory.

If you want to follow the run as-written, hold off on Secret Origin and read No Fear next, which collects #1-6.

Revenge of the Green Lanterns collects #7-13.

Wanted - Hal Jordan collects #14-20.

Sinestro Corps War collects #21-25.

Rage of the Red Lanterns comes next. The numbering gets a bit wonky here, but trust us, you’re on the right track.  (If you want to read in strict issue number order, you’d want to read Secret Origin kind of in the middle of it.)

Agent Orange comes next, collecting #39-42. 

Then we get to the Blackest Night event, which starts here.

Then back to Green Lantern. Here’s #43-52, Blackest Night: Green Lantern.

And of course you can’t have Blackest Night without Brightest Day (collects #53-62).

War of the Green Lanterns covers #63-67.

After this, you’ll want to read the three Brightest Day volumes, which are a sort of follow-up to Blackest Night.

Hope this helped!