Scheduling is done around the participants’ availability as best as possible. This is why the tournament structure is not a traditional bracket. Anyone still around in your current round mught be your next opponent, availability permitting.
Contestants are expected to find time within their matches to write and edit their entries before posting. This is challenging (especially for the 24-hour matches), but that’s the point.
The first round matches go pretty quickly (sometimes scheduled to overlap). The second and final rounds slow down a little – both scheduling and the matches, themselves.
Ideally, the first round is finished within a week of the tourney’s start. Another week or two is typical for the rest of the tournament.
If you aren’t sure you’ll be able to commit, I encourage you to sign on as an alternate when the recruitment thread goes up. Which will be soon; the judges are finalizing the format and rules for this year’s tournament.
That said, if you can expect to put in a few hours of work within the window, that’s about what you’ll likely need. And, if it’s any consolation, the earliest IRON DM matches were all only one hour!