I am viewing and working in a tutorial i downloaded called 3dplataform in wich there is an alien called Lerpz, wich works as the main character, but in the way, i am confused with assets. What is an asset and all those folder confusion? I speak in spanish and english is my second language, so i need a deeper explanation. Anyway, i am following this tutotial to activate the character as a 3rd person player using scripting, but since my unity version is a little more advanced than the one in what the author created the original tutorial, so the folder order changes a bit. Can you explain me how does the folders arrangement have changed in the new updates of unity??? Because i follow the exact instructions and my player ends up walking in the air, and it is not because of the mesh character controller, it has something to do with the folder arrangement i believe. What do you think about it. By the way today is my first day with Unity, i have never used it before. 
It is most definitely improbable that the folder order in the project is related to problems that you might face. I even think that it's actually impossible (unless of course you deleted or removed scripts or other dependencies from the original objects).
One thing you must be aware of: to correctly reproduce an original project from somebody else, you usually are better off creating a NEW PROJECT from the file menu, and then choosing "IMPORT PACKAGE - CUSTOM PACKAGE" right clicking on the project menu.
Once the import is complete, you MUST double click on the correct scene object (in simple projects you'll usually have just one scene object to select, so it's easy). If you press play at this point, things should work as intended.
NOTE: IF YOU HAVE UNITY 3.4, some older javascript-based projects might give you problems or errors after import. In those cases, access the scripts and remove the first two lines, (containing 'pragma' and 'strict' if i remember correctly), which are automatically enforced by 3.4 against unsafe programming (which was allowed in the older versions)
I’m new to Unity, and I’ve been doing the tutorial as well. I don’t think the folder’s arrangement have anything to do with your problem. If I remember correctly, the tut said that you had to fix the collider on the Y axis (1,03 or so) in order to prevent Lerpz walk on the air. Take a closer look at that part of the tutorial and you should be able to go through it.