Selling individual items as a pack

I’ve received inventory and am preparing to ship a box of inventory to Amazon. My intention is to sell the item in a pack of 4. Will I need to repackage my items in said groups of 4 or will amazon simply grab 4 individual units to make up the 4pack?

Also what would be a good cost effective solution to banding or packaging together? The items are 1″x3″x4″ square making 4″x3″x4″ when bundled together.