There's cheap and easy to attain GPS out there. Get a device with it, pick a point, and start traveling until you get back to that point. Along the way, please video the edge of the plane we are on, step over the corner so that you're perpendicular to the plane we are on and then continue along the side of Earth until you climb over the corner to be under the plane we are on. Do that for the other side and then I'll believe the earth is flat. If you don't have to do any of that but you end up back at the same point, then the earth is some sort of spherical shape, not flat and doesn't continue on for some indefinite amount of distance.
Go out there and prove it for yourself, instead of believing random con artists on youtube who just want to make a bunch of nickels from you clicking on all their videos and the hope that you'll obsessively share them. That's the real tragedy in this. Before the internet, people, if they cared enough, would go out there on adventure and find out the truth for themselves. Now, they just sit on their computer believing whatever they see pop up.