Note: you don't have to manually set the time and venue on each game – you can do that in bulk by entering your time slots. Please see the Getting Started Guide.
However, if you need to fine tune your schedule, it is easy to make manual tweaks.
You can edit almost anything about a game by
clicking on it
Venue, time, and referee are all clickable.
Clicking on the time also lets you change the date.
via drag and drop
You can drag a team onto another to swap them.
You can also grab a game by the V in the middle and drop it onto another game to swap their time, venue and referees (if any are assigned).
or through the edit game dialog
Change the week, assign assistant referees / umpires / officials, or designate a game as a friendly (scrimmage – not counted for standings).
In PRO we also have a calendar view available that allows drag and drop.
See this article for details on this.