By using the WASD keys, but you can change that in the settings to make it easier for you if you want.
you walk into them.;)
hold w down
You destroy it and walk away.
You use a, s, d and w
walk and jump
You walk, for a really, really, really long time.
No, sadly you can only walk in that normal pace sorry :((((
Walk close to the object and it will automatically be added to your inventory
On PC, it is infinite (or until Minecraft runs out of memory).
Yes, they are very cool, but watch out, because when they see you, they walk up to you and blow up in your face, and then you die.
It's some hacking device that lets you run fast, fly better, and walk through walls on MineCraft.
It is a client that allows you to fly, have super jump, super run speed, and be able to walk through walls.