How do i completely change the person i am today?

im tired of sitting here doing NOTHING with myself,it's summer and all im doing is sitting at the computer i need to clean my room exercise and have some actually fun and make memories but instead i sit here and continue to do nothing,i have no motivation to get up and make my life better and i know who i need to be but i just don't take action and change myself,how do i change?? and how do i become motivated enough to change???