You have to use CompilePal (or VIDE or Pakrat) in order to pack the assets into the map, not in order to get them into Hammer. To get the assets into the game (and, through that, into your Hammer), simply copy the folder containing the content into [Program Files]\Steam\steamapps\common\Team Fortress 2\tf\custom. Make sure all of the folders titled something like "materials", "models", "particles", etc. are contained within another folder inside tf\custom and not directly in tf\custom themselves (ex: do tf\custom\frontline\materials instead of tf\custom\materials). This should already be the case if you just copy the main folder to that filepath though, so no worries. If you're still confused, the readme.txt inside of tf\custom should explain it well enough