a nice basic introduction to Electroantennography can be found on the Syntech homepage.
Additionally I tried to explain and compare details of electrophysiological techniques in the review "Insect Antenna-Based Biosensors for In Situ Detection of Volatiles".
Finally you will find a detailed description how to handle EAD data concerning calibration for antennal ageing and inter individual variation in our article "A portable gas chromatograph with simultaneous detection by mass spectrometry and electroantennography for the highly sensitive in situ measurement of volatiles".
I added the links to these three documents below and I hope this helps your first steps in electroantennorgaphy.