no need to feel embarrassed!

the second photo is of the front cable hanger. the knurled barrel is turned all the way in (clockwise) in your photo. You should be able to turn it out (counterclockwise) which will add tension to the cable. There may also be a similar barrel on your interrupter levers.

Anyhow, to make it easier to unhook the straddle cable from your front brakes, you should first loosen the clamp bolt that secures the cable to the cantilever arm. Unscrew the front cable hanger barrel a few turns so that it is roughly in the middle of its range. Now tighten the front brake cable back down so that the pad-rim clearance is good.

To unhook the straddle cable, you should now be able to turn the front cable hanger barrel clockwise (thus lowering the cable tension) which will give you enough slack.

In terms of adjusting the pad angle with respect to the rim, you just loosen the allen bolt holding the pad to the brake arm.

Hope this helps-