Click the menu item Inventory to the left (indicated by red number 1 below).
Click + Create new, indicated by the red number 2.
Now you are in a very powerful place! Please note that you have 5 pages on forms that you can optional fill out. Nothing is mandatory. If you have tags, just start typing the pre-setup tags you have added in advance. Tags needs to be already added before you can choose them.In Page 2, Page 3 etc, you choose brand and other useful information.