Thanks. So when I am going to pass through flood, I will do a full stop first then shift to M? After passing the flood, I can shift direct to D?
Yes, better to make a full stop and think twice if you're going to proceed. You can directly shift to D from Manual mode (M) regardless of the car's speed.
What is the purpose of the + and - pala?
Like what was posted, to shift to a higher gear use + and to shift to a lower gear use -. Do not worry using this feature, if the ECU of the car detects that your speed is to low for the gear you are trying to shift to, it will simply not allow it to shift. On the other hand if the ECU detects that your gear is to high for the current speed you are in and you fail to down shift using the - the on board sensor will kick down the gear for you automatically.
I suggest playing around with this feature you have on your car to get yourself more familiar with it. It's fun to have this kind of feature.
I don't know if I am being paranoid pero parang iba na takbo ng auto ko

I know that a civic and city easily passed through the flood in Buendia but what I am worried about e baka nagshift yung auto while I drove through the flood on D

It's gutter to a little over gutter deep kasi may dip yung road.
Same question as 3GEMS, what needs to be checked after driving a flooded road?