Step1 ::: First lets see if there is anything to probe down. Drop a Multispectral Frequency Probe and start scanning. Doesn't mater what you scan on it will scan entire system and tell you the types of signals it finds. This probe only lasts 9 minuites and the scan can take that long to run but will return all signals found.

My Stats:

Skills:
Astrometrics 4   (Adds one scan group per lvl)
Covert Ops lvl 4   (10% faster scanning with probes per lvl)
Signal Aquisitiion 5   (10% faster scanning with probes per lvl)
Astrometric Pinpointing 4   (Reduces Max Scan deviation by 10% per lvl)
Astrometric Triangulation 4   (5% scan strength per lvl)

Ship Type:
Helios - Covert Ops Frigate

Rigs:
Gravitron Capacitor Rig x2 (10% faster scanning per rig)

Scan Time:
139 seconds

Now in my test run while writting this tutorial i lauched the probe as soon as i came out of the stargate. I am in a system with .6 security status. Signals it found were 1 Magnetometric, 1 Radar and 1 Unknown. I will focus on the Magnetometric Site for this Tutorial.

Step 2 ::: Now since you can drop a probe within the same scan space as another probe you need to right click on the probe and destroy it. If there was a signal to find the load up that signals Quest Probe. Note: "Unknown" results work equally well with all probe types.

Now like we said in the intro exploration sites seem to spawn within 1 and 4 AU of planets in system. The quickest way find a signal is drop a Quest probe at each planet. This is the easiest on the outer rings of a system but gets much harder as you get closer in. You will have to find the best way to get coverage on the inner planets without missing out on too much empty space that is still within the 4AU range of a planet. Once you have all your probes launched select them and start analyzing using the system Scanner

Scan Types
Drone & Probe
Scrap
Ship
Cosmic Signature
Structure

So in my case I loaded up the Magnetometric Quest Probe and headed off for the planets. Once i droped a probe at each planet i did a Cosmic Signature scan and selected all my probes by holding down CTRL and hit analyze.

Step 3 ::: Once you scan and find a signal warp to it 0km. If you do not warp into the site it self (would be rare at this point) drop a sift or comb probe and lets hone in on this signal.

The first scan reveals NOTHING... so i analyze again. My second scan reveals a deadspace signature with a .3 AU scan deviation so i warp 0km to it. I get there and nothing... so i load up a comb probe. I tried to launch it and it says the scan range is within range of another probe so i have to find out which probe is too close... i right click and destroy it and then launch my comb probe. On my first scan i get a 0km lock in on the signal... woot... now time to jump to it and see what its all about.