You must file estimated tax payments on a quarterly basis on a Form R-ES, estimating the amount of tax you will owe for the year. You must make payments on 90% of your estimated annual tax. Each quarterly payment must be 1/4 of the 90% estimate.
The first quarterly payment is due April 15th. The subsequent payments are due January 15th, June 15th, and September 15th of the current year.