Can you connect a new iphone to a iTunes that's already have a music and movie library?

I'm thinking of buying an Iphone 5s and on my lap top I have iTunes which already has a music and movie library. Am I able to use my laptop as my iphones host and use my music on my itunes and put it on my iphone?

Yep, That's the whole point and how it works. You can load up the phone by usb to the PC and make a backup copy of the phone's information that iTunes will store. Use iTunes and iCloud to store your apps, media, whatever in case the phone needs reprogramming. Best luck.

I've had several Apple devices. I can connect any number of devices to my computer through iTunes and put music on it from the same library.

One important detail - I never sync. Everybody who posts questions here says that they "sync" there iPod - I never do. My iPod Touch is nearly 4 years old and I've used only manual management. I've never had any problems putting music on my iPod, and I've never had problems that other people complain about - running out of space, not being to copy their songs to their iPods, losing their songs, etc.

manual management works fine on Apple devices old and new. I've used it to put music on a 1st gen nano and also an iOS 7 iPhone 5. It's clearly superior to syncing.