I highly recommend at least a crank puller which I see on Amazon for about $10. Some kits include other tools for not that much money. Without those tools, which really don't have the torque to do the job without causing a hernia, you begin by removing the crankset plug on the right side of the bike with an 8 mm 5-sided hex socket turning counter-clockwise. A hex socket that fits on the end of at least a 12-inch breaker arm helps. Then you insert the crank puller into those same threads clockwise, being very careful at the start to not ruin the aluminum threads on the crankset with the steel threads on the crank puller. Screw in the crank puller snugly, then insert the inside piece of the crank puller also clockwise until it bottoms out. At this point, a 14 mm hex socket with the breaker arm works best, turning clockwise, but a 5/8 wrench will do it as long as it is fairly long. Then refit the new crankset into place and re-install the 8mm crankset plug.
Watching a couple of YouTube videos helps.
