How to start a piston in Minecraft?

I know what I need but I don't know how to hook things up or whatever I do… I can't figure it out and it's making me mad lol…

Added (1). I'm trying to make a cart and ride a rail but I'm having a hard time getting away from the starting point… T.T

Pistons are part of the red stone family, they can be activated by red stone torches, buttons, pressure plates, levers, etc.
Hope that helped!

You just put redstone behind it, put a random block, and than a switch(button, lever)

Don't use a piston at all! Any time I'm building a rail and want to launch myself, I build a powered rail (that's gold instead of iron for the rails, plus a redstone under the stick to make it powered). At the beginning of the track, put the powered rail on a block one step up, so that it makes a ramp going up like this:
…/powered rail
rail---rail--/any hard block (cobble, etc.)

Put another block (not a rail) above and behind the powered rail to make a stopper. Then next to the powered rail (on any side), put a button. (one single wood block or smooth stone). Drop the cart onto the powered rail. It will stay where it is, on the ramp, because there's no power going to the rail. Hop in the cart, push the button, and the rail will be powered, and you will take off.