Newbie Help SSH User Access and Permissions

Just starting out playing with "attempting" to set up a site on a server Ubuntu 12.04.

Followed the Getting Started guide, but also added in disabling root login,

PermitRootLogin no

added (think I did) a user like this:

adduser dave

usermod -a -G www-data dave

$vi /etc/sudoers

dave ALL=(ALL:ALL) ALL

sudo service ssh restart

and I can SSH login as dave, tried root and sure enough will not allow me so everything looks good.

I SFTP thru FileZilla but i have zero permissions to create folders except in home/dave.

What Am I missing? If I grant dave all the same access as the root user why does he have none in FTP?

I can login as dave / password but cant really do anything.

My background is web development.

Never a server or command line so I am just following the guides hoping its right so the commands all or foreign to me.

Its all cryptic to a visual person so bare with me. And for now it will just be me with access.

Thanks for any all help. Explain as if I was a 4 year old if possible

Dave