Navigate to following page
Step 2:-
Click on the download now button or direct download link for FlashGot which will open a pop up box like below and ask you to install the flashgot extension
Step 3:-After restarting the browser after installing the add on, reight click on borwer window and chose "FlashGot Options" menu and then ==>"More Options" sub menu
Step 4:-Chose the path of the executable and enter the arguments as shown and then press ok
Now your download manager(FatRat) is completely integrated into your browser,You can right click on any link and press/click on "FlashGot Link" menu to add the download to your download manager