upsidedown, the "Heavens Above" website is probably one of the best for predicting where flares will be. The trouble is that it does talk about "Alt." and "Azimuth" and all that kind of stuff. I assume that's the confusing bit?
I'll try to do a step-by-step guide - please bear with me and I apologise in advance if this comes across as too basic or teaching granny to suck eggs or whatever.
On the heavens above site, your first job is to set your location. The easiest way to do this is in the "Configuration" bit, using the select from map link. That opens up a page based on Google maps. Just find where you'll be looking from, click on it in the map, give it a name at the bottom and click "submit".
Hopefully, you'll then go back to the "home" page with your location set. (If you register, you can save locations; I didn't bother - I just made the resulting "home" page a favourite / bookmark in my browser).
You can then click on the links to see when the ISS will be visible from that location, or iridium flares or whatever. This is where "Alt" and "Az", or Alititude and Azimuth come into play ..
Altitude is basically how far into the sky in degrees the object will be from the horizon: so 0 is on the horizon and 90 is overhead.
Azimuth is basically where on the horizon you need to be counting the altitude from: North, East, South or West. Or points in between.
So if it gives alt of 53 and Az of SSE, for example, look a little bit east of south (South South East) and then look about halfway between the horizon and immediately above your head.
You need to do this, of course, at the time given on the site. You should see a faint dot moving slowly across the sky, gradually getting brighter and brighter until - after 20 seconds or so - it starts to fade again.
I sometimes find it useful to look at the "whole sky chart" link in the Astronomy section on the home page. That shows you where the constellations / planets / moon are in the sky, which is handy as a guide. Remember that it defaults to "now" at your location, so you'll want to change the date and time on the sky chart page to be when the flare should happen.
The other info on the flare page is the "Intensity (Mag)", which refers to the apparent magnitude of the flare: basically, how bright it is. The lower the number, the brighter it is. And it's a logarithmic scale, so a mag 1 star is roughly 2.5 times brighter than mag 2. I think about Mag 6 is the best the unaided human eye can do from a dark site.
Most flares are between -1 and -9 and so should be easily visible in the night sky, or even daylight for the bright ones. Well, the flares themselves are typically -8 or -9 at the centre of the flare (as shown on the heavens above site) but the nature of an iridium flare means that they dim off quickly from the centre point. For example, my best sighting tomorrow night is mag -8 at the centre, but we're nearly 30 km from the centre so down to mag -1 from where we'll be.
A bit more about magnitudes: the original scale (from a looooooooong time ago) I think went from 1 to 6. But, of course, there's stuff up there that's brighter than magnitude 1, so we have to use 0 and negative numbers. It all gets a bit messy ..
