Massplanner and Followliker are some great bots you could try. However, if you just opened a Pinterest account and it's new I don't recommend joining group boards too soon. I have friends that got a few accounts insta-banned as they joined group boards very soon after account creation (didn't even get the chance to post on them before accounts got deactivated). Also, commenting can get you banned if not done properly. Best to manually comment 1-2 times a day on popular Pins and make sure you write relevant useful comments - no comments at all is even safer. If you write promotional comments these can get you banned really fast.