When you say bleached , am assuming you mean light yellow or white, and it's not 'ginger'.
If so, you're probably okay to just whack a box dye on top, just be careful to pick the right shade.
The issues arise, mainly, when it's that gingery half-way house shade. (When you're naturally very dark and bleach but need to bleach it again to get a platinum blonde: that shade!)
The 'Nice n Easy' brand usually gives consistent colour results, even over bleach.
Stay away from anything labelled 'ash' shades, as they have a tendency to go greeny on bleach, and anything too warm shaded (usually called 'golden') might go a bit orangey.
Aim for a shade one 'step' lighter than your natural colour is. Don't worry, it won't leave you with visible roots: the bleach removes the pigment, so the shade you think you naturally are on a box dye packet will probably be too dark to go on top of bleach.
Wait at least a week (preferably two weeks) after bleaching to give your scalp time to recover, and if possible, pack conditioner onto it before re-dyeing. Rather than buy one of those masks full of weird chemicals try ordinary sunflower or rapeseed or vegetable oil, slightly warmed, about half a cup full, at least twice a week.
Then, 48 hours before you're due to dye it, wash it with just shampoo, let it dry naturally if possible, and sleep on it, to let your scalp build up its natural barrier. Then apply your new colour. Use the whole amount of their conditioner, and you should be fine.