To Extract rar files all you need is the right program. You can download WinRar which isn’t free but there is a free trial or download 7-Zip which is free and can extract rar file format and many others.
After you’ve downloaded WinRar or 7-Zip install it whether you are using WinRar or 7zip right click on the .rar file and a number of options will appear. Click on “Extract Here” which extracts the file to the same location of the original file, or you could extract the rar files to a folder/directory by selecting “Extract to...” and then browse for the folder.
Photoshop folders are usually on “Program files – Adobe – Adobe Photoshop CS4 – Presets”– And then the appropriated directory for the kind of file you want to save, for exemple “Styles” or “Custom Shapes”.To use a new style on your Photoshop you should go to “Style Palette”, click on the little arrow on the left and then click on “load”. Browse the path to the folder where you have saved your new styles and double click on it. Now it should be loaded on your styles palette and you can start playing with it.