It's in the top-right corner of the screen on mobile. Desktop users will instead click Create board on the left side of the page. It's toward the bottom of the screen on mobile. If you're on desktop, skip this step. This title should reflect the kind of content you plan on posting to this board. Doing so will create your Pinterest board. Now that you have a place to store content, you're ready to upload and save some pins. You can also hide your board from other Pinterest users by selecting the Keep board secret switch (called Secret on desktop).
Select the + button. Select Create board. Type in your board's name. Select Create.