S2 Q&A: Should I resign from my H-1B job now to get ready?

No - resigning ends the status you must keep while the change of status is pending. Stay employed and in status until the consultant's timeline says otherwise; the COS is filed after admission and I-20, and you hold your current status while it's pending. Please don't give notice before we talk: https://goelite.com/meetings/wending/initial-consultation.