Nothing but the rules compendium at the table.
Ask the DM or CoDM if you need a clarification on the rules.
Whenever possible, talk at the table should be in character. This is not a hard rule, because sometimes group clarification is needed. But I will be reminding you guys to ask more questions through your characters. Questions or discussions for the DM and Co-DM is fine, but working out strategies, finding out information, beefs, and many other things are best handled in game.