A spread will give a sort of sub-question to the card that gets placed there
The three card past preset future spread, for example
The first card represents something in the past, maybe something that's hindering you now, or something that can help you move forward
The second the present. What's going on at the moment, due to the past?
The third is the future, with a potential outcome for if nothing changes
Celtic Cross uses ten cards
http://www.learntarot.com/ccross.htmAnd there's one that they tell you to set aside at LEAST three hours for cuz it uses literally the
entire deckAnd no I will not be doing that last one, ever
And yes, it is possible for someone to create their own spread. Using Shadowscapes and SenBasa together would be an example