How or where can I claim my second stimilus payment since I didn't recieve it ??

To claim your stimulus payment, in the TurboTax Online program,  

• After sign in to your account, follow prompts
• To your left, select Federal
• On the next screen, from the top, select Other Tax Situations and Done with Others (at the bottom)
• On the screen, Let's make sure you got the right stimulus amount, select Continue
• Select "Yes", enter the amount you have received for both stimulus payments and follow prompts

If you did not receive any amount, enter zeros.  The program will calculate your Recovery Refund Credit amount as the stimulus payment you are entitled to.