am a new user in Autodesk Revit structure 2013 , when i open the program and start to creat levels , the Elevations (Building elevation) is invisible the project browser , so i can not creat the levels, please see attached file
1- You are on a plan view (level 1) so you will not be able to see any elevations.
2- The screen shows the modify wall contextual ribbon, which means that you have selected a wall.
3- To create levels, you need to be in an elevation view, and then you can create levels from the home ribbon or by copying the existing level and changing to a plan view.
It appears that you are not using any template.
I would reccomend starting from a template. If one of the supplied templates is not what you need, modify it and save a new version for use in the future.