A season is the fundamental structure in which a RackEmApp league operates.
A video guide to this can be found here.
The setup process is provided in stages/steps, and requires that you complete some pre-requisites before you do this, so be sure to watch the videos.
Seasons are found in Administration > League Management > Seasons
You'll be presented with your season list, which may be empty if you are a new league. The season list contains a list of all the seasons in the system. Which includes legacy seasons (read more in Perpetual Management to understand what these are for).
To create a new season, click the New Season button. To edit an existing season, tap the season name.
You should only have one active season and one draft season at a time. If you have multiple draft season the system will get confused identifying your “NEXT” season, which it uses in multiple places.
You can make basic edits to the Basics, Teams and Divisions pages whilst a season is inflight. However if you need to alter the other screns, like adding a team or altering fixtures then you must Unstart the season in the Basics screen, which it will only allow you to do if there are no results in place.
Besides that, the full season process is documented on the below links.