That's because Homegroup has been removed and that affect also other network operations.
That's how I have setup my network with Win 10 1803.
Most important part is to start some required services.
That make your PC's visible in File Explorer network devices.
Push Win Key and type "Services", locate those services, start them and set Start type to Automatic (Delayed Start).
- Function Discovery Provider Host
- Function Discovery Resource Publication
- SSDP Discovery
- UPnP Device Host
One more is missing, SMB , in programs , in windows features.
the long play( Huge ) and full detailed answer is here, if you want to read 10 pages.