Well, at 1:30am today, I did the deed. And I will be showing you all the steps I took and more importantly how the newly improved Windows OS version looks like.
Stage 0: Backup your phone
As a heady geek, I skipped this stage. But please don't in your case.
Stage 1: Install Windows Insider app
Go to the Windows app store and install the Windows Insider app. You will need it to enable your phone see Windows 10 mobile update.
Stage 2: Configure the Windows Insider app
All you have to do is set it to enable Insider Previews. (I chose Insider Slow option)
Stage 3: Check for and install update
After your phone reboots at the last step of the Stage 2, you will now be able to see and install Windows 10 as an update.
It took me some time to download and install. At a point I was worried the phone had freezed when I didn't notice any progress for the first 10 minutes of update installation (the spinning gears part).
Unfortunately, I have no screenshot for this stage.
Stage 4: Welcome to the new Windows Mobile.
Everything looks very cool and lovely in the Windows 10 mobile. Unfortunately, my phone call history and SMS history were wiped off. I also had to setup my email accounts all over.
Enjoy the many screenshots I took to show you what I mean.