Indiana Code Title 34. Civil Law and Procedure § 34-57-2-2

Sec. 2. Arbitration shall be initiated by a written notice by either party, mailed by registered or certified mail, or delivered to the other party, briefly stating a claim, the grounds for the claim and the amount or amounts.  Issues shall be joined by written notice of admissions or denials and any counterclaims or set-offs so mailed or delivered.  The statutes of limitations ceases to run from the time of any notice of claim or counterclaim.