Putting music from itunes to iPhone?

I use one computer for my songs in iTunes. I have an iPod Nano (3rd gen) and it's already synced to the computer I use (which is the one I'm using right now to ask this question).
I got the iPhone 5 pretty recently (Sept 26th), and I want to put the songs that I have in my iPod Nano onto my iPhone 5 for those moments when I don't wanna bring both with me. How would I do this through iTunes?
BOTH of these devices use my same apple account, so how would that affect the iTunes thing if I just plugged in my iPhone? I'm just worried that if I just plug my iPhone in that it'll erase the songs that were synced to my nano.
I'm really confused because I don't want any of my songs to get deleted. Long story short: I want the same songs I have on my nano to go in my iPhone as well (without accidentally deleting anything or messing anything up permanently).
I'm not super techy, so please be as specific as possible! Oh and I use Windows (I think it's Vista?)

Added (1). @MrMoustache person, I don't really understand what you mean by "taking both"? And when you say that it'll erase the iPhone 5 stuff, did you mean that it would only replace the music on it (if there's any)?
Oh and I forgot to mention that my iPhone 5 has NO music on it whatsoever, it's a clean slate basically except for some apps and stuff.

Are gel iPhone cases protective?

I recently got a iPhone 4S and I LOVE it but my mom is really paranoid about it cracking so she got me this big grey and black case. It seems very durable but it's really ugly and big, I can't even put it in my pocket. She won't buy me another case (although I ordered a Stitch case on amazon, but it's going to get here around Halloween) so I asked my friend if I can borrow one of her many iPhone cases. So I came home today with my friend's gel case on my phone and my mom got mad. Are gel cases not very protective? Maybe it's just that the phone is new and that's why my mom is paranoid but honestly I don't think I will drop this phone. I have had a Nintendo DS lite, a iPod touch, and 4 phones in my lifetime. Not once have I ever dropped any of those.

What is this Chinese movie called?

I saw this movie on my way to china on China Eastern Airlines. It was about a guy that has a crush on the girl in university. They live in the same area, take the same bus and take the same route home. Then something happened that I don't remember but they talk to each other and the girl finds an abandon house and cleans it up to take pictures. I also remember they had a Sony Walkman and had this CD that they listened to and at the end of the movie, he gave it back. Then the movie goes to the guy smoking in an office building and all grown up. Then the girl he liked about 5 years ago(I think) came up to him and asked him to design her a house. Her father never had time to build it and was in the hospital at that time. At the end of the movie, her dad finds a picture of him on her iPhone and asks "Who is that" and she replies with "Hes just… A friend"
Then I cried.
I don't remember any names but I think the area that they lived in was jungguhou something and her name was seong juong or something. It may be Korean but I'm not too sure. I have been looking for that movie for ages

How to sync 2 apple devices on one iTunes account?

I have an iPod touch 4. And just recently got an iPhone 4g. I have 32GB on the iPod, I have all the music I want and games on there that I please, however my iPhone is only 8GB. I only want to download a couple apps and about 100 songs onto seeing as how the memory is so limited. I unchecked the apps so that they wouldn't not ever sync automatically, but when I synced my iPhone it immediately tried downloaded 200 apps that I all used to have on my iPod. I went on the apps and deleted the apps I don't want on iPhone and only had 20 left over. I synced and I got all I wanted on iPhone… However now I'm afraid to sync my iPod in fear that's it gonna delete all my apps until I just have the 20 that I have on my iPhone.

I'm selling my 64GB iPhone 4S on ebay, how much should I sell it for?

I got an 64GB 4S, I got it brand new from sprint a couple of weeks ago. I'm selling it with an gameboy case, the original 30 pin charger and dock connector and earbugs. I'm also selling it in the original box. I was planning to sell it for around $550. Its also in brand new condition. Do you think this is an good price to sell it for? Its also white too.

Who thinks the iPhone 5 is a waste of money?

To me I'm a Windows and Android fan but I have heard that the iPhone 5 is a waste of money and why would you need to upgrade anyway its a ripoff. I have to use apple everywhere I go cause my school uses it for everything and its annoying apple. To me windows is easier to use well back to the question, Why do apple have to make the iPhone 5 complicated with a different docking input and why is it apparently a flop?

Added (1). IPhone 5 is apparently a waste of money?