>> do I have to do the Kernel build too when I do the CVSUP and buildworld?
Not always but recommended. Say you are already tracking 4.4-STABLE and just buildworld + cvsup with the latest src for today. Then you plan to cvsup and buildworld again tomorrow, the diffs (if any changes) may not be significant enough to cause your kernel to fail. For 4.4-RELEASE -> 4.4-STABLE, recompile a kernel is almost a must.
>> not sure where to start
1) Check your disk space, make sure you have plenty of free space (600mb at least) on /usr.
2) Extract all src from your CD to /usr/src, then recompile a kernel (based on 4.4-RELEASE src).
This way, after cvsup and recompile your kernel, you almost don't need to alter your kernel config file again at all.
3) Create /usr/local/etc/cvsup/src-supfile with the following context:
*default host=cvsup8.FreeBSD.org
*default base=/usr
*default prefix=/usr
*default release=cvs tag=RELENG_4
*default delete use-rel-suffix
*default compress
src-all
4) Run cvsup /usr/local/etc/cvsup/src-supfile
5) If /usr/obj exists, rm -rf it and mkdir it again
6) Then follow FreeBSD's handbook's Ch. 19.
Note, the handbook says you buildworld first, before reboot, recompile a kernel, then reboot and "install world". These procedures look very lame to OpenBSD and NetBSD.
Right after cvsup, you should recompile a kernel immediately, reboot, then buildworld and install world, then merge your /etc and make all in /dev and finally, do a reboot.
So what are the differences in doing FreeBSD's way and Open/Net way?
FreeBSD way is safer and extremely conservative. It assumes your buildworld will fail, then their way is safer and easier for recovery for newbies. In Open/Net, the way is aggressive and assumes your buildworld will be successful and actually have a higher percentage for a successful buildworld. The recovery, in the event of a buildworld/recompile kernel failure after reboot, all you need to do is to boot up your /kernel.old instead of /kernel.
Why Open/Net way has a higher chance over FreebSD way?
Recompile your kernel first before buildworld and installworld ensure your new kernel can understand all the new changes.
So which way should I go for?
Go for the FreeBSD way since this is your 1st time, so it's better to do it safely and expect a failure and do recovery.
When you get used to buildworld and recompile kernel, you can go for the Net/Open way.
Anyway, not trying to scare you, you will have a high percentage of a successful upgrade from 4.4-RELEASE to 4.4-STABLE.