I have participated in the beta program going back to my S7. I for one am extremely disappointed in samsung. From what I've been reading on some sites it has not even popped up yet, even XDA which is a highly reputable source for Android devices, software, mods etc... Has stated It isn't available yet. Take a look through the thread and see what else you can find there.
Edit: As of now, the unlocked models with U1 firmware are the ones that have beta. If you want to sideload or craoss to U1 instructions can be found int he same thread posted below. Nor I or XDA take any responsibility for data loss or damage to your device. this is at your own risk. Kind of silly to do for a beta, but if you are that desperate, by all means.