I'm running Ubuntu 13.04 on my computer from a live USB. I'm not able to watch Youtube videos. Am I able to install adobe flash and if so how do I add it to the live USB.
You may need to enable persistance, if you want to install once and use it after reboot. Please check this https://help.ubuntu.com/community/LiveCD/Persistence#Introduction (Thanks @Henry Gibson)
And you have to enable multiverse source.
Now, execute these commands to install Flashplugin in Ubuntu 13.04