Bro recommended engine oil, suzuki geniune 0w-20 fully synthetic
Regarding maintenance, engine oil+oil filter change interval is 5K kms
1st gear oil on 10K then at 40K
Air filter every 10K
Secondly Regarding your purchase, congrats, enjoy the ride
Ignore others
Personally if I choose an entry level sedan, I will prefer yaris over city (as its launch is expected in 1st qtr 2020, not too far)