1.are they climbing or dwarf varieties?
2.which virieties(if you know)?
3.height of the plants and general condition of them
4. do you want them to hang over a fence or what?
5.winds/frosts in the area(usda zone)?

All Bougainvilleas thrive in full sun in a free-draining, soil-based compost. They require a night temperature that does not drop below a minimum of 10ºc (50ºF). Water freely during the Summer months, but very sparingly in the Winter. Use a high-nitrogen liquid feed in the Spring and change to a high-potash one when the flowering begins. Bougainvilleas are not self clinging and must be tied to their supports.

Pruning....Cut back the previous seasons lateral growths in Spring; only spurs up to 3cm (1 1/4 in) long should remain.

Hope this helps :)