Each option is a rule, not a contract: where you finish depends on what the others hold.
the options are always North-South's, so this brings the other side's problem round to you
Indentation is the tree and * is the fallback. Edit it here and press Load, or paste one someone has sent you.
An option is a call you might make. Under it, each row asks a question about one player and names the contract you reach if the answer is yes. The rows are tried from the top and the first match wins; if none match, the default row applies.
A contract is written as the contract, a colon and who plays it — 4S:N, 3NT:S, 5CX:E. Write Pass on its own for a board passed out, which scores nothing.
+ add a branch adds another question at that level, tried after the ones above it. then asks a further question once a row has matched, which is what makes it a tree — three levels is the limit. Remove the last question at a level and it folds back into a plain contract.
The second line under each result shows where the hands actually finished. A contract at 0% means a row that never fired.