It comes from the root "bruiken". Bruiken is cognate with an archaic use of the word "brook" in English, which meant to use or enjoy, which is still used in Scots but spelled brouk. Also Swedish bruka, etc.
The "ge-" is used for past tense in German and multiple uses in Dutch. For example, the German cognate is "brauchen" (ich brauche, I need/employ/use [archaic usage]), which takes the form "gebrauchen" (ich habe [__] gebraucht) in the past tense. At least, that's what I can piece together with my limited knowledge.
"Wij" and "we" both mean "we." The difference between them, however, is that "wij" is used when you want to emphasize the pronoun. For instance, you may want to say, "We do not use pepper," although others might use pepper. "We" is used when you do not need to emphasize the pronoun. Knowing that, depsite the fact that pronouns such as "wij," "zij" and "jij" are seen more often on here, you would actually be more likely to use "we," "ze," or "je," if I am not mistaken.
Hope that helped!
We gebruiken peper.
The direct object of the sentence above is __peper__ -- and in this case it would be considered a __non-specific__ direct object. Thus you would use geen instead of niet to negate the sentence:
"We gebruiken geen peper."
If the sentence was: __We gebruiken de peper__ -- then the direct object, de peper, is specific. Thus you would use niet to negate.
"We gebruiken de peper niet."
Some characteristics that would define a direct object as specific would be:
preceded by a definite article (e.g. de, het).
preceded by a demonstrative pronoun (e.g. deze, dit, die, dat)
preceded by a possessive pronoun (e.g. mijn, jouw, hun)
names of people, cities and other proper nouns
Specific Direct Objects --> niet
Non-Specific Direct Objects --> geen