In order to don a disguise you need to find an NPC that will offer you one at a price of gold bars. This quest only requires you to don the disguise and nothing more. The locations where you can find the relevant NPCs is below.

Raz can be found at Colossal crops.

Bushranger is to the southwest of Pleasant Park.

Crustina is inside The Pizza Pit just south of The Orchard.

Jekyll is inside Steamy Stacks.

Snow Sniper is to the east of Retail Row.

Map credit to fortnite.gg