Start by clicking on one of the buttons that you can see on the home page, the image that you can see in them is related to the banking that they do.
After picking what banking you want to use you will have to click on "Sell [item/banking name]" if you want to sell your items. If you want to buy from our bots then you will have to scroll down a bit and select one of our bots or click the buy button if there's any so they show up.
You should be able to see your backpack or the bot's backpack and also be able to pick the items that you want to buy or sell. When you finish picking which items you want to buy or sell and with what you want to pay, you'll be added to the queue where you'll have to wait for your turn.
When you're in the front of the queue the bot will send you a trade offer and a notification will appear on scrap.tf giving you the options of checking the trade offer that the bot has sent you.