I have always wanted to donate, but due to anaemia, have never been able to. I believe all you need to do is make an appointment and show up. They may stick your finger for a couple of quick scans (to check for things like anaemia), then have you lay down while they take your blood. You will either be provided with some-thing to eat/drink after, or can take your own in order to avoid any potential light-headedness. The process is very simple. What you want to do is great -- if it hadn't been for people like you donating, my father would have died long before he did.