Drag & drop the "Reimagined" folder into your "mods" folder inside the Call of Duty: Black Ops root directory
This is assuming you already have game_mod installed which is required for BO1 Reimagined to work https://github.com/Nukem9/LinkerMod/releases
This is a fork of BO1 Reimagined with light tweaks and revisions based on my own personal taste (as someone who made a similar mod for WAW with my own style that wants to make both mods flow well in unison)