How exactly do you put a item up in the market and set the price number?

The items board is the wrong section to ask this question. Moving to beginners sanctuary.

Also to put an item up in the market you click on the picture / thumbnail of the item when it is in your deactivated inventory. This brings you to a page where you can set the price of the item. Once you click update, the item will then be in the market at that price. You can remove the item by going to your market items and selecting the remove item from market link.