On ours, one side is easier than the other. So I open that side first and then run my fingers under the flap to the other side, while pushing up on the tab with my other hand. It snaps right open. It's not a very good design, IMHO, and the one on our old hybrid with the tabs that turned to hold the flap in place, worked much better.
Geoff & Jill
& Sierra, the little white monster
2013 Ford F-150 XTR SC Ecoboost
2015 Jayco Jay Flight 24FBS