Windows 7 and Windows 8 have built in Chinese Fonts. It is free, you may use your English keyboard to input Chinese character. Nowadays, modern Chinese use pinyin method. If you can write English/German with your keyboard, you may use the same keyboard to write Chinese.

You can use Chinese pinyin.

well, we also use the English pc-keyboard to type, but we have to used the input software at the same time. Different software indicates different method of typing. For example, if you use “五笔”, you have to know the structure of the Chinese character well and recite many radicals and their position in the keyboard.(I don't use this way, either. XD) if you use"拼音", you just need to be familiar with the pronunciation of the Chinese character and type in the right order of the syllables.(many people use this, including me XD) And I know there are some software that you can draw the whole Chinese character with the mouse. That's all I can tell. Good Luck! :)

i use google input method. Here is the download address. http://www.google.com/intl/zh-CN/ime/pinyin/index.html

If you're using Windows, go to the language settings in the Control Panel and add Chinese/Mandarin (whatever it is). Then you can set a keyboard shortcut to switch between English and Chinese keyboard layouts, or alternatively, you can switch by using the language bar.