docs: added a how-to guide for customer groups (#2362)

* docs: added how-to guide for customer groups

* added link to new documentation

docs/content/advanced/backend/customer-groups/index.md

@@ -56,4 +56,5 @@ The relation between the `PriceList` and `CustomerGroup` entities is available o
 
 ## What’s Next 🚀
 
+- Learn [how to manage customer groups using the Admin APIs](../../admin/use-customergroups-api.mdx).
 - Learn more about [Price Lists and how they work](../price-lists/index.md).

docs/content/advanced/backend/price-lists/use-api.mdx

@@ -1,7 +1,7 @@
 import Tabs from '@theme/Tabs';
 import TabItem from '@theme/TabItem';
 
-# Use PriceList API
+# How to Use PriceList APIs
 
 In this document, you’ll learn how to use the PriceList Admin APIs to create, update, and manage prices in a price list.
 

docs/content/advanced/backend/sales-channels/manage-admin.mdx

@@ -1,7 +1,7 @@
 import Tabs from '@theme/Tabs';
 import TabItem from '@theme/TabItem';
 
-# Manage Sales Channels
+# How to Use SalesChannels APIs
 
 In this document, you’ll learn how to manage sales channels and their products and orders using the Admin APIs.