Sharing Folders over LAN

So this thread is about an issue which two of us had where the sharing service via Samba from one computer to another didn’t work.

In my case when right-clicking and then filling in “Share with Samba” it seemed as if everything works fine but when you shut down Dolphin and then open it you notice that it has reverted back.

This is a normal behavior. The shared folders are not saved through sessions but need to be set for every session. At least I never saw it working another way.
For permanent changes you need set up smb.conf (see https://wiki.archlinux.org/index.php/Samba for this)