You are purchasing a non-shiny bundle of 5 Pokémon that evolve through trading. The Pokémon in this bundle are Alakazam, Genger, Golem, Machamp and Alolan Golem. Select "Trade" and you'll have a screen pop up to select a code. You will have 10 Pokémon to choose from to create a three-Pokémon code, this is to make sure that only we are the ones that connect to each other. Once found, your Pokémon box will be shown and you can select the Pokémon you wish to offer for trade. You can also see what Pokémon your trade partner is selecting at the top of the screen. After both parties select their Pokémon, they'll go to another screen where both can either accept the trade, or check the Pokémon before accepting. You can also cancel the whole trade, which will bring you back to your Pokémon select.
eBay