Flavourful Titular Titles v1.11 for Base and CK2+ addon

Open the .zip file. Inside you will see 2 folders:

Sweet Vanilla vX.XX
Vanilla Plus vX.XX

Open the Sweet Vanilla folder if you are running NO OTHER mods.

Open the Vanilla Plus folder if you are running the CK2+ mod. (don't know what this is? You don't have it then :) )

Drop the contents of whichever folder you picked from above into your mods folder (as listed below). You should be dropping a folder called ftt and a file called ftt DIRECTLY into the mod folder. If no mod folder exists, create it

For Steam:
X:/Steam/steamapps/common/Crusader Kings II/mod

Otherwise:
/Crusader Kings II/mod