My apologies for the delay.
If your arbitration is to be conducted through AAA, here is the arbitration demand form, and notes on how to file: http://www.adr.org/aaa/ShowPDF?doc=ADRSTG_004175
If your arbitration is conducted through some other forum, you can follow their procedures (look online for your specific arbitration group), or if there is no specified forum, you can send a demand similar to the one above regarding arbitration to the opposing side - there should be an arbitrator or arbitration service specified in your contract, but if not, using AAA is commonly recognized.
If you decide to go through with arbitration, you should prepare to pay costs and fees that are roughly similar to going through civil litigation
(arbitration initially was started to reduce fees, but as a practical planning matter, I would advise considering this for a good estimate for costs.
If you hire an attorney, your odds of success increase (they know the procedural and legal standards much better than a lay person, and can give you a significant edge - you will need to decide for yourself whether this edge is worth the expense).
Unfortunately, I do not have a good cost estimate for this type of arbitration - depending on the negotiating positions it may be very low cost (the parties can settle quickly), or high cost if there is a larger dispute.
I hope the above is helpful, and again, I apologize for the delay.