Try watching Rick's free friday tutorial on NURBS, it's a good introduction and answers your questions. He made a video of doing the exact same thing with polys, if you'd find it useful to watch the comparative workflow let me know because I have the video here (somewhere in my mess) so I'll find it and upload it if you're interested.

Maya NURBS tips and tricks. SimplyMaya Free Friday Tutorial on Vimeo

Also Jay did a glass jug with revolved surfaces which is helpful if you're completely new to NURBS.

https://simplymaya.com/autodesk-maya-...=164&sub_cat=0