Explain the prosses of removing the president from office. what role does the house representatives play?

It's called the Impeachment Process. 
The House Judiciary Committee decides whether or not to proceed with impeachment. and if they decide to do the Chairman of the Judiciary Committee will propose a resolution calling for the Judiciary Committee to begin a formal inquiry into the issue of impeachment. 
Then on the inquiry they decide if the impeachment can go forward or not. Then the Full house votes on each article on Impeachment. 

If the articles on impeachment are approved, the president will be impeached.