To alter a 'Products' title and/or description, from the store dashboard go to:
> Products > All Products

From within this page find the 'Product' that you'd like to alter the title and/or description of, either by scrolling through or searching for it via the search box in the top right:

Once you've found the product, hover over it with your cursor and click 'Edit':

The title of the product can be edited from the top text box, and the description of the product can be edited by the large text box below it:

(*Don't forget to click 'Update' after making alterations*)