kaiiii said

I can not see the settings ap in my firefox window. This leads to that I can change my language and other things please help...

Are you talking about the window that you can change Firefox's settings in? You can always open the settings by pressing Alt on your keyboard to show the menu bar and opening the settings by clicking Tools>Options.

If you want to add it to Firefox's menu, click the menu button, click Customize, then drag the "Options" icon into the menu. Visual representation of that here: http://s27.postimg.org/w3daygao3/add_options_to_menu.png