Until now, everything you've said in German has been real: things that happen, happened or will happen. The Konjunktiv II is for what isn't real — wishes, polite requests, things you imagine. English does this job with would, could and were.

Two forms come up constantly: wäre (would be, were) and hätte (would have). They're built from the Präteritum war and hatte: add an umlaut — and an -e where there isn't one already:

Pronoun	sein →	haben →
ich	wäre	hätte
du	wärst	hättest
er / sie / es	wäre	hätte
wir	wären	hätten
ihr	wärt	hättet
sie / Sie	wären	hätten

The umlaut makes all the difference: ich war = I was, ich wäre = I would be; ich hatte = I had, ich hätte = I would have.