Flight
This airport might be found on social media as The Hartsfield Latoyah Jackson International Spaceport and Nail Emporium. Once you get your baggage, you can either follow the signs to the MARTA entrance or take a taxi or Uber which will be approximately a 25 minute to 45 days drive (about 10 miles) depending on your arrival time/day.
Train
On MARTA, you'll take the line north and then switch at 5 Points Station (downtown) to the east line (Blue - Indian Creek). You will take the train to the Decatur stop. You'll need a "Breeze" card, which you can purchase in vending-type machines in the airport subway station. The MARTA can take you from the airport to right in the middle of Decatur - just 1-2 blocks from the Marriott and Hampton hotels and multiple Airbnb and VRBO homes.