You must file an 83(b) election within 30 days of the date you received the restricted stock. The election must be made with the specific IRS office where you file your annual tax return, and you must include a copy of your 83(b) election with your annual tax return.
An 83(b) election directs the IRS to tax the stock at the time of the grant, when it may be worth very little or when payment is made, minimizing potential tax liability. The downside:...Taxes are paid on stock that is eventually forfeited. Here you could incur tax on unrealized net income. Also, the value of the stock does not increase over time. Here you will have paid tax earlier than if you had not filed the election.