WoW: Classic is scheduled for August 27 (technically August 26 if you're in the Americas). The soonest that you can play it is starting in May, during Blizzard's scheduled stress tests. To opt-in you must have an active subscription on your account. If you do, go to Account Management and select the Wow Classic beta. Keep in mind, there will be level caps during the test. The schedule is as follows:
A demo of the game was available at BlizzCon 2018, and was downloadable on home computers for anyone who purchased a BlizzCon ticket or virtual ticket. The servers became available when Opening Ceremony started at BlizzCon 2018 and was set to end on November 8, but was extended until November 12.[4] Players started at level 15, and the only available zones were Westfall and the Barrens.[5] It was based on patch 1.13.0, essentially patch 1.12.0 ported to a modern infrastructure. The first day of the demo, there was a playtime limit of a cumulative 60 minutes with a cooldown of 90 minutes, applied through the BlizzCon Exhaustion debuff.[6] The debuff was removed on the second day of BlizzCon 2018.[7]
Here is a clip I just recorded on Beta with 42 ping: As you can see there is significant delay between the time I hit the command and when it moves, both with the attack and follow. It was not consistent, some had longer delays. The last one in the clip was the worst; I haven't timed it but it appears to be approx 1 FULL SECOND. This is NOT a lag spike, I am experiencing no lag at all with character abilities.
 ":"  -  Any time a step ends in a ":" instead of a "." means that the next step is part of the current step you are on.  This generally means the next step should be done while working on the current step.  This means every "start working on" or "continue working on" will end in a ":".  But this is used with other occasions as well, so keep this in mind.