A/C Line Plumbing Questions Options

[Coomer]

Right now I'm working on trying to get my A/C to work in my car, and I've got a couple questions.

1. There's the large silver line that goes into the firewall and hooks up to the A/C compressor. Then there's the silver line that goes into the firewall and hooks up to the A/C condensor(I think that's the name of it...it's the radiator-looking thing) and finally hooks up to the A/C compressor. My question is, which line goes to which part of the compressor?

Here's a picture to illustrate this:

The circled things are the places where lines can attach.

2. On my spare 4A-GE, the lines are still attached to the compressor, but they're cut. However, they've got these big metal things, pictured below. What do these things do? I know that my '95 ST doesn't have these. And do I need them? I planned on using my ST lines on my car.

Pictures:

There's the 4A-GE compressor.


For comparison purposes, here's the 7A-FE compressor.

Attached image(s)