You need eight tin cans - assuming you have a bed with four legs.
Four of the tins should be a couple of inches smaller than the other four.
Ensure that the bed/bedding is not touching a wall or any furniture,
Stand the bed in the four small tin cans, which are in turn in the larger cans. Pour about an inch of parrafin or white spirit (turpentine substitute) into the larger tins and keep it topped up.
Do not smoke in bed.
Using a vacuum cleaner with an upholstery nozzle and going over the matress paying particular attention to any edgings or folds should clear out quite a few of the adults, but it can take some time to clear an infestation - it is a matter of keeping going over everything, moving everything regularly, completely stripping the beds, washing bedding, filling cracks and crevices and squashing everything that moves on more than four legs.