Configure SharePoint Client Permissions

I need a SharePoint specialist to open up my existing site to external clients while keeping the rest of the environment locked down. The goal is to let named client accounts enter the Documents Library and the Project Files area with full Edit rights—upload, modify, and delete—without exposing any other libraries, lists, or team sites.

Here’s how I picture the engagement:

• Set up or confirm the correct external sharing settings at the tenant and site levels, then grant Edit permissions only on the Documents Library and Project Files.
• Verify that clients can sign in with their own Microsoft or business accounts; anonymous links are not acceptable.
• Provide a quick walkthrough (screenshots or a short call) so I know how to add or remove individual client users in the future and audit their activity.
• Before we wrap up, test the access end-to-end with a dummy external account to be sure nothing else is visible.

I’ve already enabled SharePoint Online; you just need to configure these specific permissions and show me the ropes. If you can handle this smoothly and keep security tight, let’s get started.