Heroku is a cloud provider. This means you will not have to run your bot on your own computer. It will run on the Heroku cloud. When creating your free Heroku account, it will ask for your credit card information. This is because some dynos can cost money on Heroku but steem-fossbot-voter was designed to operate within the free account. Even several copies will not break into the paid services that Heroku provides. It will not use your credit card without you upgrading your account manually. By the way, I don’t work for Heroku. I’m only a user. So far, I’m using the voting bot as a free account.

In GitHub, go to the steem-fossbot-voterproject.
Scroll down until you get to ‘Installation’.
CLICK THE PURPLE BUTTON: DEPLOY TO HEROKU

FILL IN THESE FIELDS:
STEEM_USER: Put your Steem account name here without the @
POSTING_KEY_PRV: Your private posting key goes here
BOT_API_KEY: a password for your bot
Note: this should not have any spaces and be random, for example:
AOUNA039NA9SDJ
THAT IS ALL THE REQUIRED INFO YOU FILL IN.
You can leave these blank:
EMAIL_ADDRESS_TO
EMAIL_ADDRESS_SENDER
SENDGRID_API_KEY
You can leave these as the default:
COOKIE_SECRET
VERBOSE_LOGGING
HIT THE DEPLOY BUTTON
Wait a few minutes. The deployment can take several minutes and below the deploy button you will see it happening. Give it time to complete. If you have a failure because of sendgrid you can contact Heroku support and they will fix it. I had to create a support ticket in Heroku for the sendgrid issue, but it was resolved quickly.

The reason you need to fork the project is to ensure that your voting bot gets automatically updated when changes are made to the GitHub project.