Is it an unitypackage? If it is, its pretty simple, I'm sure you know how to import a unitypackage. You have to create a new blank project, then when unity is open, on your project you wish to import your assets, click on the .unitypackage file (If it is a unitypackage) and there should be a popup menu giving you options to limit what you import.
However if it's just a folder with assets inside, if they already set up a scene, you can open the scene with the whole project, by just locating a scene they made that comes with the virtual world kit. You can double click the scene (not in unity) and it will automatically open up unity, and load up the game.
Or another way you can open up any other project, is you can go to file> Open project> open other and locate it.
I hope I helped, if you still couldn't get it to work, I may do a video tutorial.