A group is one leader account and any number of followers. Each follower carries its own sizing so that a $25k evaluation and a $150k funded account can follow the same hand without the small one blowing up.
One group is one source account
How many groups you may have is what the plans separate: Manual has one, Algo and Unlimited have as many as you want. Followers are never counted — adding a target account is unlimited on every plan, which is the whole promise on the pricing page. A group that already exists is never taken away. See Plans and billing.
Per follower
Risk in dollars
The amount this account should risk per trade. Contracts are worked back from the stop distance, so every account risks the same money rather than trading the same size.
Max contracts
A ceiling, applied after the calculation.
Minimum stop distance
In points. Guards against a tiny stop turning into an enormous position.
At least one contract
Rounds up instead of skipping the trade when the maths lands below one.
Leave the risk empty
Copy the leader's size one for one.
Closing works the same way as opening: when the leader flattens, the close is copied. The group also has its own flatten, which closes every follower at once.
Every change to a group — created, paused, follower added, sizing edited, deleted — writes a line into the event log (under "All"), so "when did I change that" has an answer you can read instead of remember.