This is a guide on how to use Mann Vs. Machine part banking.

I want to sell some Mann Vs. Machine parts for metal, how do I sell these?

This is the Mann Vs. Machine banking page. Click the "Sell Parts" button to begin.

You'll be in a queue once you've pressed the "Trade Now" button.

You're now in the queue to sell your Robo Parts. You can see the queue at the top of the screen. I'm currently in a "global queue" which is what you'll be in at the start. Then you'll be assigned to a bot to trade with it. You might be in a queue for a minute or so. 

Now this will pop up. Click the green "Go to trade offer"

You'll now get into a trade. Simply accept the trade if everything is alright.
When the offer is alright and has gone through then the trade will be closed.

You'll now see this. You now have your metal. Simply close it by clicking the white X at the top right of the box.

You've now succesfully completed a Mann Vs. Machine Robo Part trade! Congratulations!
It's basically the same with all the other trades, but. You can always go and check those tutorials as well.