How to set my nikon d700 to autofocus when I hold the shutter button half way?

My d90 does this and I can't figure out how to do it with the d700. Please and thank you!

^^I only have a manual for my d90. And I'm not sure if it is

Page 72-73 of your user manual tells you how to set it up.

Also is the lens set to AF mode?

Download your manual from Nikon.
https://support.nikonusa.com/...a_id/13948

Your D700 has the ability to autofocus with any AF Nikon-mount lens. You just have to set the autofocus switch to AF. I'm not familiar with the Nikon system but I recall my son's D50 having an AF switch on the body and another on the lens itself. To be sure, set both to AF (away from M).

And yes, you can download the manual for free at Nikon's website.