This is not a simple job. It's one of the most frustrating. Don't ask me why, but getting information on this topic is...difficult.
I mistakenly put the front valve inside the foot box and didn't realize until 8 months later that I did it "wrong". You need to buy fittings to complete all the connections. I went through so many iterations that I would need to check my receipts to see what finally worked.
You may also want to try to remove the black fitting on the valves and ensure there is a rubber seal and spring inside. And that they move. You may have to heat up the valve to get the fitting off. If you heat it up too much, you may melt the valve. If the smaller brass fitting on the other end leaks, dont even bother with it. Throw it away. Those things are maddening. They're difficult to install, and to not leak. I wound up splitting the flare on the end of one of the short lines you pictured because I over tightened it. Thankfully it was simple to replace because it was small, but it wasn't exactly cheap.
Depending on your philosophy, you can resign yourself to making those damned things work, or make life easier and buy the Wilwood versions. But the Wilwoods are shorter in length and if they're surrounded by hard lines, that can be a difficult conversion.
A.J.