Help! myGallery dont work :(

I have tryed to follow these guidelines:
http://wordpress.org/support/topic/60714?replies=25

What do this means: “upload mygallery to the plugins folder
create a folder called ‘myfotos’ inside the ‘wp-content’ folder
chmod the ‘myfotos’ folder to 777
activate the plugin”

What is chmod? and whats up with 777?

PLease tell me how i can get this to work (i am a nooooooooooooooooooooooooooooooooooooooooooooob)

see http://golfsiden.net/php/?page_id=37 (it is where i am trying to add the gallery)