If you are currently in the U.S. on a B status, it is unlikely that you will have enough time to start the Labor Certification process and complete the adjustment of status (AOS) from within the U.S.
If you are not in the U.S. but have a B visa, an option is to start the EB-3 process from outside of the U.S. Then, once your Labor Certification (LC) is approved and your priority date is current, you can plan a temporary trip to the U.S. on a B status.
It’s important to remember that the B visa is not dual intent, meaning that you must have the intent to depart the U.S. after the temporary trip. You can enter the U.S. on a B visa after the LC is approved, but your intent at the time of entry must be for a temporary trip, leaving the U.S. at the end of your stay. You need to have evidence of your intent to return to your home country and continued ties to your home country. If your intent later changes and you decide to adjust status after you enter, you can file the AOS, but we generally advise waiting at least 60 days from your last entry on a B status.
Once you file for AOS, you must remain in the U.S. until Advanced Parole (travel parole) is issued, and you are not permitted to work until your Employment Authorization card is issued. Since this usually takes 5-8 months, you need to be able to stay in the U.S. during this period without earning an income in the U.S.