Some people say a lower takes 15, 30, 45 minutes, whatever. Don't worry how long it takes someone else to do it. Take as long as you want, it's not a race - the important thing is to do it right. I took over an hour on my first build but it ended up right the first time, mainly because I triple checked every step.
Watch a few good videos before you choose one. You'll get little tips from each video so remember them. Brownells videos are good plus you can print out their PDFs with the same instructions. It's handy to have it printed out as you do the lower.
As far as tools, I just used what I had in the garage. Nice to have specialized tools but not necessary for the lower.