In your bot's Twitter properties you can configure it to retweet or process/reply to tweets with specific keywords or hashtags.

Normally a bot will perform a Twitter search to find new tweets for it to process. You can configure your bot's Twitter search in its "Tweet Search" property.

You can configure your Twitterbot to retweet posts from your bot's Twitter page in its Admin Console.

A Twitterbot can retweet posts from its friends, or from a tweet search.