There are a variety factors that are used to determine if you qualify for the third stimulus check.
Please see the link below for all of the requirements.
How will the 3rd stimulus affect me
If you determine you do qualify, please use the following links from the IRS to check your payment and where it is in the IRS system, as well as another link with more questions answered by the IRS in regards to the payments.
Link to check your third stimulus payment
FAQs for Stimulus payments