Navigate to the section that you want to add the new item to.

Tap on the large green action button on the section screen.

Tap on the "Create a new item" button

Tap on the "Name" form element and type in the name you want the new item to have. If you want to give the item a description, you can tap on the description form element and enter in the description you want the item to have.

Tap on the check mark icon on the top right hand side of the screen to create the item.

After it's been created, new form elements will appear on the screen where you can add content such as: prices, media, etc.