In general terms, a term set is a curated dictionary of words and phrases specific to your business operations. A term set is usually organized in a hierarchy of less specific to more specific (such as Country > State > City). In SharePoint, a term set for managed navigation can only be associated with one site within a tenant. You'll need to repeat this procedure for each site that you want to configure with managed navigation:

1. From the SharePoint Admin Center, select Classic features, and then select Open under Term store:

2. If this is your first time administering the Term Store, you'll need to grant an account the appropriate permissions. In the tree-view navigation pane, select Taxonomy_<id>, and then add an account to Term Store Administrators and click Save:
   

3. Click on Taxonomy_<id>, then select New Group:

4. Fill out the properties for the name of the group managers and contributors and then click Save.
5. Point to the new term set (or an existing one if you have previously configured a group to be associated with a site), select the arrow that appears and then select New Term Set.
6. Enter the value that you want to use as the default label (or name) for your term.
7. In the Properties pane of the Term Store Management tool, click the General tab.
8. On the Properties page, specify the following information about the new term set:

• Term Set Name: Enter a name for your term set if you want a different name than the default.
• Description: Enter a description for using the terms.
• Owner: Specify an owner. You can enter only one item.
• Contact: Enter an email address of a user or group for feedback purposes.
• Stakeholders: Add the names of business users or groups to be notified before major changes are made to the term set. The users listed here are not granted any permissions—it is only a text field for business review purposes.
• Submission Policy: Specify whether you want the term set to be Open or Closed.
• Available for Tagging: Select the checkbox to make the terms available for tagging. If the term set is still in development or not ready to be deployed, clear the box.

9. Click the Intended Use tab, and then configure the following settings:

• Available for Tagging: Check this box to make this term set available to be used for tagging items.
• Use this Term Set for Site Navigation: Select this checkbox to enable this term set to be used for managed navigation.
• Use this Term Set for Faceted Navigation: Check this checkbox to enable refiners based on managed properties on the pages with managed navigation. This is an advanced setting.

10. Select the Custom Sort tab. Select the sort order that you prefer if it is different from the default. By default, terms will be sorted alphabetically for the current language. Select Use custom sort order so that you can organize terms to always appear in a consistent order.
11. Select the Custom Properties tab to specify any additional shared property name and value data about the term set.
12. Click Save.