The Accessories tab is one of the product tabs which appears with product details in each of these screens: the Catalogues screen, the Search screen or when you view Suppliers > Individual Prices
Open the 
Catalogues window and locate a product using the Search options to access these options on the Accessories tab.
Linked accessories are products that are related to the main product. E.g. fixing kits. They can be specified in the catalogue originally and you can add your own product accessories. Accessories will display as a prompt to select them when you add the main product to a quote. You can select or ignore them.
Note that this Accessories tab is not designed for furniture or door products (which are priced in price groups) but for single priced "flat" products only. For more advanced capabilities consider using Assemblies instead.
1.Click 
Add to open the Add Product screen
2.Click the magnifying glass icon to search a product you want to link to.
3.Enter the quantity you want and tick compulsory if you want to ensure the linked product is always added.
4.Click 
Update to save and you will see the product appear int he Accessories tab.
You can repeat to add multiple linked products.
Click 
Delete to remove an accessory link