When to use 'waren' and when to use 'hatten'?
I have had trouble differentiating between waren and hatten for a long time. In what context would you use 'waren' or 'hatten'? (If possible, give example sentences! Thanks!)
You're asking for examples, yet you aren't very specific in what you do not understand between these two verbs. Wir waren/wir hatten is a clear distinction you also make in English: "we were/we had".
I suspect you are referring to the past perfect tense: wir waren gegangen or wir hatten es getan. Just like with the present perfect, some participles take sein as an auxiliary verb, others haben. This is something you have to learn, as it's not always fully logical why all of the sudden a form of sein is used.
As far as waren/hatten are concerned, these are simply forms of sein and haben respectively. Ich bin gegangen - "I have went"; ich war gegangen - "I had went"; Ich habe es getan - "I have done it"; Ich hatte es getan - "I had done it".