Hi Lavonia,
1. No, there isn't any manual avalaible, but you cn use this
tutorial.
2. The contacts are just the users of your site, from the groups you selected in the component configuration.
3. You can control which group can acces to the application form or not. To "block" access, you can select "special" for example. Like this, only administrators and super administrators could access the forms.
4. To change a text, you just need to edit the language file, that you'll find in the folder /components/com_neorecruit/language.
Regards,