Are battlefields flipped/revealed before or after determining who goes first in game 1?

Ruling: Battlefields are selected simultaneously and placed face-up in the battlefield zone (a public zone) before determining who goes first. Players should select their battlefields at the same time to prevent one player from gaining information advantage.

Sequence:

• Players display legends and champions
• Players simultaneously select and place battlefields face-up in the battlefield zone
• Determine who goes first using a random method
• Draw 4 cards and determine mulligans

Nuances:

• The comprehensive rules don't explicitly describe a "face-down then flip" process, but simultaneous selection (whether by flipping face-up or placing face-up simultaneously) prevents information advantage
• For games 2 and 3, the loser of the previous game decides who goes first/second, and this decision happens after battlefields are placed in their zones
• Trying to see an opponent's battlefield before selecting your own could be considered angle shooting