To simplify an algebraic expression, all you have to do is add all the like terms.
Example:
2w+w+5x+3w+x
First, you would do 2w+w+3w. Your answer would be 6w. Then, you would do 5x+x. Your answer would be 6x. Finally, your final expression would be 6w+6x.
Hope this helps! :D