It's pretty simple: Unpack Unity Mod Manager anywhere (except to the Breed Laboratory folder) and copy the UnityModManager.BreedLab.xml file into the same folder you unpacked UMM into like this:You can show how the folder should look, or the video should be done how to put it all?
Run the UnityModManager from that same folder, select the game from the drop down, and then select the main folder for the game, so it looks something like this:
Click the install button and it should install. From there, you can click on the Mods tab and drag the zip files for the mods onto there to install them, but that should be self-explanatory. You do not need to extract the zip files yourself.