Hi !!
 first you go to the home option then go to marketplace (Altcoins) and click Bounties (Altcoins) and get your project which you want to do easily , Read there instructions and do as they mention in Rules. This is the simplest way to join Bounty program. And remember check spreadsheet of bounty that you choose , after filling the applicant form your name will be mentioned in spread sheet then you can start your work .. !!