You can use a household surface spray or a dust. For severe infestation, use both. Some sprays have attachments to help direct spray materials into cracks and crevices. Apply enough spray to moisten surfaces thoroughly, but not enough to drip or run. This material doesn't kill the roaches, but it will flush them into the open where they contact a residual surface spray or dust.
Baits work well to keep a population under control after using an insecticide.
Put out a good number of baits. For best results, place them where the roaches live. Beneath the kitchen sink and drain board. In cracks around or underneath cupboards and cabinets, and inside them, especially in upper corners. Places pipes or conduits pass along the wall or go through it.