linux sdl2 installation

[Ceset]

hi guys

i m very new at linux

and when trying to install sdl2 i come across with a problem.
i use kdevelop and cmake and in SDL2-2.0.1 folder there exist a README-cmake.txt file. i followed the orders given there.

Assuming the source for SDL is located at ~/sdl

cd ~
mkdir build
cd build
cmake ../sdl

This will build the static and dynamic versions of SDL in the ~/build directory.

and my sdl folder is Downloads/SDL2-2.0.1/ and i did it as it says and here is the error

ceset@Ceset-PC:~/Downloads/SDL2-2.0.1$ mkdir build
ceset@Ceset-PC:~/Downloads/SDL2-2.0.1$ cd build                                              
ceset@Ceset-PC:~/Downloads/SDL2-2.0.1/build$ cmake ../SDL2-2.0.1                                    
CMake Error: The source directory "/home/ceset/Downloads/SDL2-2.0.1/sdl" does not exist.     
Specify --help for usage, or press the help button on the CMake GUI

what should i do

EDIT: package managers have support for sdl 1... versions but no sdl 2 and i currently use kubuntu

[Ceset]

omg i did not didt ../SDL2-2.0.1 and instead i did ../ and it worked fine