This works when cannot download/install from M store.
PC Manager may be downloaded through Microsoft Store - Generation Project (v1.2.3) [by @rgadguard & mkuba50]
1. Click the above link in your browser.
2. Select "PackageFamilyName" on the search bar's left side drop menu.
3. Copy "Microsoft.MicrosoftPCManager_8wekyb3d8bbwe" into the search field.
4. Click on the right side ✔ symbol.
For some reason, adguard.net will sometimes not find this App. Probably because some of its servers are not located in the US. Keep clicking the ✔ symbol a few times until you see a result.
5. When presented with a list of files, click the link for: Microsoft.MicrosoftPCManager_3.9.3.0_neutral_~_8wekyb3d8bbwe.msixbundle
Your browser might block the download for security reasons. The provided link goes to a legitimate MS server.
6. From File Explorer, click on the Microsoft.MicrosoftPCManager file and Windows will install it for you.