Between the two shops at the FutureWorld entrance to World Showcase.
Check in is on the Mexico side of the shop on the Mexico side. Look for a kiosk booth there.
Once you check-in they usher people into a holding area. Then they'll let everyone in as a line into the viewing area. Don't panic. There is plenty of room inside to spread out. Get yourself a table first, then send parties over to get food & drink items. The biggest rush is right away to get a table and then get food. After about 20 minutes the lines disperse and it gets a lot almer. The food and drink do not run out.
Have fun! We really enjoyed it ourselves.