Help with iPod nano?

IPod Nano and itouch 4G HELP!!! URGENT.?

• Okay, so i have this computer, its crappy and slow and i have itunes and my ipod plugged in there and stuff, and i have this fast laptop with itunes installed and stuff. so i plug in my ipod nano in the laptop and i transfer the songs to itunes.. because it was originally plugged in the other comp. so, now that the ipod nano is plugged in i click under the music and it shows all of it, which is good. BUT how do i basically sync the songs in my library, that way when i unplug my ipod nano all the songs show up in the library, so when i plug in my ipod touch 4g it can sync the songs in the itouch. ANY ANSWERS WOULD BE APPRECIATED. THANK YOU. SORRY IF I WAS NOT CLEAR ENOUGH.

• Answer:

  In iTunes, under devices on the left side, click on your iPod. Then near the top there will be multiple options such as music, videos, etc. Click music then check Sync Music