Go to relevant category and click on 'add new product'.
Add title (product code) and save.
Upload a photo and save.
Click on 'Edit title and main details' then 'Add more detailed text and formatted tables'. From here you can add to the various product tabs eg. Information, Size and Colours.
editing
Find the product you wish to edit and click either 'edit' or the product name.
Following directions to the part you'd like to edit (as per No 4 above)
deleting
Find the product you wish to edit and click either 'edit' or the product name.