1. Open the default "Regular Checking Account" online
2. Fund it with an existing Citi AAdvantage MC or Visa (not Amex) credit card, where you hope it won't be tagged as a cash advance (YMMV)...setting your cash advance limit at zero in advance may help prevent unpleasant surprises. You can open your new checking account with up to $30K (maybe more) from your Citi CC, if your line of credit is that high. You can fund with only one credit card, and only for the initial funding.
3. You have to keep $6K at Citi to avoid monthly checking-account fees. You may not need this full balance in the account(s) for the first month or two.
4. Avoid any option to get paper checks, unless you are prepared to pay $19 for them.
5. Give a landline phone number for "home phone" if possible, rather than mobile number.
6. Make note of your new account number at the end of the sign-up process online.
7. Make 5 or more purchases each month using the Debit card as a Credit card (no PIN entry). If you miss a month, you're SOL.
8. The Offer Code is CEET, and that is already filled out on the webpage.
9. After 3 months you get 10K AA miles, and 9 months later you get another 10K miles.
10. Be mentally prepared for delays and errors on Citi's part. Be aware that Citi has a reputation for sometimes not giving miles due.