Scheduling a team based activity with 10 different teams and X different games. Every team must meet each other ONCE but never twice,

Scheduling a team based activity with 10 different teams and X different
games. Every team must meet each other ONCE but never twice,

Hi there I am planning a "Scavenger hunt"-like activity (I have no other
words for this event), and I am having trouble creating the schedule.
The idea of this hunt/run/game/competition is that 10 teams will battle
each other at X different mini games. The games on are team vs. team
based, meaning that there will always be two teams on each post and one
winner and one loser.
I require that every team fights every other team. Meaning that team 1
will have to meet team 2, 3, 4, 5, 6, 7, 8, 9, and 10, and team 2 will
have to meet team 1, 3, 4, 5, 6, 7, 8, 9, 10 (and so forth). The amount of
mini games must be so, that every team only meets the other teams ONCE
each, but still they have to meet every team.
How many posts do I need to create, and how could I schedule the overall
activity? (A table of rounds and teams would be much appreciated).