@andyhanna1958 Hi,
Collections are very flexible in that they aggregate stats from any game included in them.
You can add a game to a Collection from Game History, or right at the end of a game, which is the easier way to go.
For a single season replay, you’d need one Collection.
Plan on playing two seasons and want to aggregate career stats between them and have separate stats for each season? Either use three Collections (season 1, season 2 and combined), or use one Collection and flag/unflag included games when you want to change the stat breakdown (having three Collections is the easier method, I think).
You can create a Collection for free and try it out with games played with the free teams. You can always delete the Collection later to make room for another.
To maintain a custom roster for the purpose of trading, etc. you would need the Custom Teams unlock. It will allow you to create a roster that can be filled with any players you have access to. There is a search feature for selecting pitchers and position players, by year, team, some stats, etc. You can add in bulk (for example, search for the 1920 Yankees pitchers, select all of them and add to the roster), or one at a time (search for 1920 Carl Mays, select and add to roster).
Finally, both you and your opponent must own the teams they play with. Teams cost $3, and gift certificates are available in the store.
Have fun,
Jeremy