1.  go to http://www.webkit.org/building/checkout.html

this link has svn repository information
2. Run command to check out the WebKit source tree:
alen@Alen-Vostro-1550:~$svn checkout https://svn.webkit.org/repository/webkit/trunk WebKit

The above command will take time depending upon your network speed. After finishing of svn command Webkit is downloaded in Webkit folder.
1. WebKit is top directory
2. Under Webkit various subdirectories for different components are there.
3. Like WebCore in Source/WebCore, for WebKit2 in Source WebKit2
4. For Building, updating source tree from svn,Test case running various automated scripts present in WebKit/Tools/Scripts directorry.
5. You can list sub directory by running ls  command llike


Building Webkit for beginners may not be good experience as it requires lots of depedent library like libgtk,libxml2,libcairo,libglib,libgail and many more. Before building Webkit on Linux/Windows you need to install these library. If you are having linux system ( Ubuntu,fedora,centOs etc) then you should use their respective package manager for installation of webkit dependent library.
1. Ubuntu uses Synaptic Package Manager
2. Fedora,centOs use YUM installer

WebKit can be built by diferent way but it is better to build from WebKit/Tools/Scripts dir. Let  alen@Alen-Vostro-1550:~$

be terminal.

Run Below command from Top Webkit Dir.

  alen@Alen-Vostro-1550:~$./Tools/Scripts/build-webkit –gtk

if above command succeeds then webkit will be built in WebKit/WebKitBuild/Release directory. Enter into this directroy and see what is built. You can run simple Bowser example from this path. The library usually is built in .libs directroy inside  WebKit/WebKitBuild/Release dir.

During building may  some build error due to lack of dependent libarary or misatch of required version of dependent library come. You need to take care of those errors.
You can see link http://www.webkit.org/asking_questions.html for asking question on webkit guidelines.