Welcome! I like your car.
White 6th-gen civic.
Your automatic transmission should be fine with engine-off coasting at any speed below 35 (spec in the manual). You can do it above that with reasonable caution, too. What kind of drive do you have? Your automatic has better gear ratios than my manual, so it's a better highway cruiser than mine. In town I can do more with the manual because I can get the exact rpm/load I want.
Getting up to speed - find the shift points and let up on the gas a moment when you get there. Once it shifts, you can lean on the pedal again until the next shift point. Once it's locked into top gear (45 mph?), try to keep it locked. A downshift will eat a lot of extra gas.
I'd suggest getting an Ultragauge or Scangauge before trying a Kiwi.