Newbie question about relations

[Boy-Oh-Boy]

Hi, I am new to FM, and I am ploughing my way to The Missing Manual. (I am currently on page 303.) :

Could someone lend me a helping hand: what I would like to find out, is how I can have FM opened the next option only if the previous condition is met. E.g.: does this person join the dinner - if so, how much did she pay? Does she have a special diet - if so, what diet?

Topics like these are hard to trail in the program or the book. I'd be very happy if someone could point me out where I should look.

Now I am going back to the book… page 304… :

[Fitch]

Are you talking about related value lists?