Log into your Ameritrade account and tap in Account/Bank Connections inside the My Account section.

Then, make sure to have Electronic (Bank ACH) selected, and tap in New connection.

Choose Checking as your Account type, and Yes to confirm it is your personal account.

Enter your ABA routing number (you can find it in ABA/Routing Number in the "Receive" > "Dollars" > "ACH (Standard)" section of DolarApp).

Enter your bank account number (you can find it in Account Number in the "Receive" > "Dollars" > "ACH (Standard)" section of DolarApp).

Confirm the bank account number.

Type a name to keep your DolarApp account saved in Ameritrade for future withdrawals.

Tap in Continue and make sure all data is correct.

Go back to My Account and tap in Withdraw.

Click in Transfer to your bank (Transfer money to your bank (ACH)).

Select the account that you want to withdraw to (look for the name that you entered in step 7).

Enter the amount you want to withdraw and the frequency of these transfers (this is in case you want this transfer to be repeated periodically, if not just leave One time as your option).

Select the date in which you want to execute your transfer (if you want to execute it that same day you don't need to touch anything) and tap in Continue.

Review all the transfer details are correct, and click in Submit to execute the withdrawal.

And that's it! Your transfer will arrive in 3-5 business days max, and you will have your DolarApp account linked for future withdrawals.