Go to Origin.com and log in. Once logged in, go to the Battlefield V game tile and select "Try First"
This will start the download process. The file is 12.44 GB in size. All others can download a few days later.
I played a round before work, the servers are having some issues. I needed to join through the server browser, quick play would result in an endless black loading screen. Also, the squad system was broken. You can view or join squads which is weird since it worked fine in the second alpha.
I give a shit how far they postpone the game. Postpone it till the cows come home just make it work as a complete game on release. I was thrilled when they pushed back Hardline 6 months because it would have been a shitshow on the original release date. I gained a LOT of respect for DICE because of that.. which they immediately squandered with BF1.