Follow these steps to purchase mods in Fallout 76:

1. Write to the seller and check if he is online.
2. Pay for the purchase and receive a unique 16-digit code.
3. Tell us this code and your nickname in the chat.
4. Specify which type of mods you want to purchase.

Select New mods for Gatling plasma or Plasma Enclave

The seller will send a request to friends in the game. As soon as you accept the invitation, the seller will move into your world and meet with your character.
The order is executed immediately if the seller replied to you in the chat or within a maximum of 24 hours.