Hi partner,
In CRM, for products, we use the product catalog to manage them.
The product catalog is a collection of products and their pricing information.
Please refer to https://docs.microsoft.com/en-us/dynamics365/sales-enterprise/set-up-product-catalog-walkthrough
In Sales Hub, we can see Products in 'Sales' Area and Product Catalog in 'App Settings' Area.

The product catalog itself is only used to create and manage products. In order for products to be associated with customers, we need to use entities like Opportunity, Quote, Order, and Invoice.
Within the forms of these entities, there is an inline sub-grid dedicated to editing their products.
Taking Opportunity as an example, the Account and Contact on the form is the customer, and the sub-grid under the Product Line Items tab is used to edit the products of this opportunity.

The same applies to the remaining entities. Potential Customer in the Quote form indicates the customer, and the Products sub-grid is used to edit this Quote's products.

This way, in Sales Hub, we can sell products to customers.
For the complete sales process, please refer to this document: https://docs.microsoft.com/en-us/dynamics365/sales-enterprise/nurture-sales-from-lead-order-sales