The following packages will be affected by setting up Sharing Sets:
Framework
PagesApi
OrderApi
Eventapi
CPBase
LTE
Configuring Guest Profile:
Navigate to Setup > All Sites and click Workspaces for your desired Community Portal. Select Administration from Workspaces.

From Administration, select Pages. From Pages, select Go to Force.com. A new tab will open onto the Site Details page for your Community’s Portal.
Click Public Access Settings. The Custom Portal Guest Profile page will open.
Click Edit and scroll down to Custom Object Permissions.

Make sure View All and Modify All are unchecked for all options. Click Save to apply your changes.

Close out of this tab and return to Settings in your org.
Next, configure your Community Profiles.