[ADD] Sales: New accessory products page

Author: theRealThagomizer

content/applications/sales/sales/products_prices.rst

@@ -12,3 +12,4 @@ Products & Prices
    products_prices/returns
    products_prices/ewallets_giftcards
    products_prices/loyalty_discount
+   products_prices/accessory_products

content/applications/sales/sales/products_prices/accessory_products.rst

@@ -0,0 +1,52 @@
+==================
+Accessory products
+==================
+
+The use of accessory products is a marketing strategy that involves the cross-selling of useful and
+related products alongside a desired core product. Accessory products are automatically suggested in
+eCommerce interactions when a customer views a shopping cart with an associated core product in it.
+For instance, by configuring accessory products, a customer could be suggested a sleeping pad or a
+camping pillow when they view their shopping cart with a sleeping bag in it.
+
+.. note::
+   Accessory products are differentiated from optional products and alternative products by where
+   they appear in the customer's shopping experience.
+
+   - Accessory products appear as suggestions when viewing an eCommerce cart with an associated core
+     product in it.
+   - Optional products are suggested when a core product has been added to a cart or a quotation.
+   - Alternative products are suggested at the bottom of an eCommerce product page whenever the
+     product page is viewed.
+
+.. figure:: accessory_products/accessory-products-ecommerce.png
+   :alt: A screenshot of an eCommerce shopping cart showing accessory products.
+
+   Accessory products as they appear in an eCommerce website shopping cart.
+
+Configuring accessory products
+==============================
+
+To add an accessory product to a product form, navigate to :menuselection:`Sales --> Products -->
+Products` and choose a product. Ensure that the product's :guilabel:`Sales` checkbox is ticked and
+click the :guilabel:`Sales` tab. Under :guilabel:`Upsell & Cross-sell` heading, the
+:guilabel:`Accessory Products` drop-down menu allows for accessory products to be set. Products will
+be displayed in alphabetical order. If the desired product isn't readily visible, type its name in
+the field to bring it up, then select it to add it as an accessory product.
+
+To delete an accessory product from the product form, simply click the :icon:`fa-times`
+:guilabel:`(Delete)` icon.
+
+.. image:: accessory_products/accessory-products-product-form.png
+   :alt: The accessory products section of product forms in Odoo Sales
+
+Additional products can also be added to a core product by clicking :guilabel:`Search more...`. This
+opens the :guilabel:`Search: Optional Products` form, which displays all products in the catalog and
+includes the :guilabel:`New` button to create a new product. Multiple products may be selected as
+optional products at once when using this form by ticking their checkboxes and then clicking
+:guilabel:`Select`.
+
+.. image:: accessory_products/search-accessory-products-form.png
+   :alt: A screenshot of the Search: Accessory Products form accessed by clicking "Search more..."
+
+.. seealso::
+   :doc:`../../../websites/ecommerce/products/cross_upselling`