I know this is a year old but, the "Day Version" of this map comes with enabling CS:S. If you don't know, how just look at the bottom right corner and you'll see a Controller Icon. Click on it then you'll see a bunch of games when you see "Counter-Strike: Source" there should be a box. Click on the box, then boom, just like that you have enabled CS:S.

good idea

You should already have it if you have counter strike source, which you should because it's required for this map to work properly