Bitcoin Forum

I have a couple questions for anyone here willing to help me out. It may seem that I'm asking this in the wrong place but keep in mind that I am creating this live USB Boot for Ubuntu so that I could store my bitcoin on there.
I was following the directions on here: https://help.ubuntu.com/community/Installation/FromImgFiles (https://help.ubuntu.com/community/Installation/FromImgFiles)

At first I ended up on a pitch black screen asking me if I wanted to install Ubuntu or simply try it out. I scrolled down to "try it out" (or something like that) and pressed enter on my keyboard. (my keyboard was functioning when this option popped up)

I will mention that when I was creating my bootable usb I did cancel the "sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m" command in the middle of the process because after I entered the command I didn't notice an immediate result and therefore assumed that nothing was happening. I did get a warning when I closed the terminal that if I close the application the current process will also be closed. (I know I should've realized there that indeed "something was happening")

Anyway, after this I repeated the command a second time after opening up the terminal a second time and this time I waited and the terminal seemed to have a completed the process.

1st question: When I hold option upon starting my computer and it takes me to the alternative drives to start up, I see two boot options. Why is this? (this is after I pressed enter on "Try Ubuntu" on the previous screen)

2nd question: When I'm on the screen to choose a drive to boot from it also gives me the option to choose my network
connection should I choose the network then? I ask this question because when Ubuntu was booted my wireless mouse and keyboard didn't work. (I'm still on the same screen  described on my last post)

3rd question: Also after Ubuntu loaded I couldn't use my mouse or keyboard and also an error popped up saying that some audio application on Ubuntu had to quit unexpectedly. Why did this occur?

Lastly since I could move my mouse or use my keyboard I just restarted my iMac using the power button behind the computer. This all occurred just now, so if anyone can help me out with this I would greatly appreciate it. Thanks in advance!