The instruction/manual is extremely bare and doesn't say anything except connect it. It's meant for the US market after all.
Already planning to pay to do hacking for this if required to. Been asking wireman around and no one would do it as they are unfamiliar.

Yes, kena import tax on the whole thing. I bought the set with the August Smart Lock, Doorbell Cam and Smart Keypad. Did not consider the Ring. Reason for it is for airbnb digital lock - so I can remotely deal with digital keys, unlock remotely and a physical keypad in case digital is not my guest's cup of tea.
I think that's right - the doorbell is just a switch. Again, my reason for using it is for Airbnb purposes - where it makes sense as my unit is in Cyberjaya and I'm located in KL. Remote unlock for guests, digital keys and keypad unlock all will make 24 hr check in useful.
Right now, I don't have an existing indoor chime unit. There are the wires:

but I've not bought a unit yet.

Are you saying that I can buy a unit that has a transformer built in and then the switch would be 16-24V as it is a loop with the wire there? Any idea what kind of chime unit has that in Malaysia?

Thanks all for your input!

Yep, finally got it done! 
1. Actually it's pretty center of the plate. But perhaps the angle of that photo makes it look as if it's one sided, and the wedge which is installed to make the camera face towards the right. If I remove the plate entirely, the doorbell is too small for the box it's in, and can't mount it properly, as the mounting screws for the concealed box is horizontal in the center like this the wall conceal box in this photo:

while the August's wedge mounting is:

Not the red circled ones, but the two on the upper left and bottom right. Would be a bit weird and difficult to glue it fit.
Here's another angle of the doorbell cam installed:

Anyway, yes, once I have more time I'll go out and find more options to figure this out to make it neater.

2. Yes, even before I had the doorbell cam installed, and when I'm in KL (My property is in Cyberjaya), I was able to assign guests on the go. That means I'm out of reach to the Bluetooth, and the smart lock was not yet connected to the internet. I was surprised as well, as the main purpose I wanted to install the doorbell cam was to be the internet gateway for the smart lock.

3. I will do that on my next visit to my property and post an update.

Cheers!

No, this is not what I mean
1. I did not have August Smart Doorbell installed at that point (Smart Doorbell = Gateway), connects Smart Lock to the Internet
2. I was not in Bluetooth range
3. I can add a guest as long as I have internet connectivity to the user list for the lock
4. The guest will need the internet connection to receive the virtual key. This can be done way before the check in time, for example, or anywhere with internet basically.
5. After receiving the virtual key, let's say the guest goes to the door, via Bluetooth can unlock the door directly through the virtual key. The guest does NOT need internet connectivity to unlock the door.