You need to imagine scales as being a circle, hb, not a line ... makes it much easier to understand. The little scale clock below teaches all kinds of things about scales. Just remember to end on the same note as you start on, and understand that it's an octave above the original:
Starting at C, as per the arrow, you have the major scale: TTsTTTs ... the Do Re Mi Fa Sol La Ti Do scale.
Starting at D, the Dorian mode ... TsTTTsT
Starting at E, the Phrygian mode ... sTTTsTT
Starting at F, the Lydian mode ... T T TsTTs
Starting at G, the Mixolydian mode .... TTsTTsT
Starting at A, the Aeolian mode ... TsTTsTT
Starting at B, the Locrian mode ... sTTsTTT
So all those modes, including the one you're asking about, the Aeolian, are just the same set of intervals-in-a-circle, using different starting notes.
The Am scale and C scale aren't the same in between.
If you were to start on C#, not C, all those intervals would shift by one 'hour'. It would certainly look more complicated with all the sharp signs, but it would be the exactly the same relationships. Each 'hour' is one of the 12 notes, and this simple little template just shifts around for each one.
Thinking chords, now: Grab any of those lettered notes (call it 1), skip a note(2), grab the next(3), skip another(4), grab the next(5). That's a chord: 1-3-5
Starting at C: C E G > C major (look at the distance from C to E. 4 'hours' ... major third, makes a major chord)
Starting at D: D F A > D minor (see how the interval between the 1 and 3 is smaller? Minor chord.)
Starting at E: E G B > Em (again, the 1 to 3 distance is a minor third, 'three hours.')
Starting at F: F A C > F major (back to a major third between 1 and 3)
Starting at G: G B D > G major (another major third interval between 1 and 3)
Starting at A: A C E > A minor (back to the '3 hour third', makes it minor)
Starting at B: B D F > B half dim (here the intervals between 1>3 and 3>5 are
both minor thirds. Makes it half diminished, the odd one out, the fly in the ointment.)
Does that make it clearer?