[Samba] File verification

[Henry Kwan]

I am fairly new to the Linux and Samba worlds and stumbled onto the Louis Van Belle's download page of Samba 4.5.5 backported to Debian Jessie.  Thanks for the backport, Louis.
Since I am new to Linux, Samba, and GPG, I simply cannot figure out how to verify the Samba 4.5.5 tar files from Louis' download page.  These files are supposed to be signed and the public key is given in the "louis-van-belle.gpg-key.asc" file.  I have the following questions regarding verification of these files:
1. How do I verify that the public key given, the "louis-van-belle.gpg-key.asc" file, is legitimate in the first place?2. How do I use this public key to verify that the tar files are good; aren't there supposed to be corresponding signature files as well?
I tried verifying these files on my Debian 8 system and a Windows 10 PC (using gpg4win) but was not successful.  Any help given to this novice is appreciated.
Best regards,
Henry Kwan