"Attempted possession"? Is that what your citation actually says? or did you come up with that?
Anywho, while Isis is wise to advise you to find an attorney, that may not actually be a necessity. If you have never been convicted of anything else before, then you may find yourself in a potentially "okay" situation. The state of Arizona tends to be quite lienient with first-time offenders of non-violent crimes.
At your court date, you will be asked how you plea. If the judge does not automatically offer it as an option, request a pre-trial conference. At this point, you will be given a new court date, at which you will have the opportunity to speak to the prosecutors. It is more than like that they will offer you deferred prosecution on all charges. This process entails paying court fees (anywhere from $300 to $1200 depending on the county), attending drug/alcohol classes, as well as a [extremely] light probation, the sucessful completion of which will result in the charges being dropped.
Now, if you have some sort of criminal record here, then definitely do not attempt to proceed with an attorney at the helm. And, despite the advice I've given, even with a clean record it really is not a bad idea to retain an experienced attorney. The best attorneys will be the ones with offices across the street from the courthouse. Yes, they can be pricey, but that tends to be because they are worth it. A local attorney knows best what the courts want to hear (and also are more able to brush the proper elbows and can get deals with the acquainted prosecutors that the average layperson would not be able to attain) and as such present the highest potential in yielding the most favorable results. Many attorneys will offer free/cheap consultations, so there is nothing wrong with, at the very least, sitting down with a couple to see what insight they may have to offer.