Short answers, pulled from the story.
Parliament passed the law in March 1534, though legal calendars at the time began the year on March 25. Officials recorded the legislation as occurring in 1533 due to this calendar convention.
Elizabeth stood as the daughter of Henry VIII and Anne Boleyn when the new law declared her heir presumptive to the Crown. She had been born on the 7th of September 1533 before the legislation elevated her status.
The legislation stripped Mary of her royal status and legally bastardized her to alter the line of succession. This move removed Mary from the direct path to inheritance while elevating Elizabeth based solely on parliamentary decree.
Refusal to take the oath designated any resistance as treason under the Treasons Act 1534. The charge could lead to execution for those who resisted the mandatory requirement regarding the king's authority over the church.
The Second Succession Act made Elizabeth illegitimate again and undid the status granted in 1533 or 1534. Subsequent changes came with the Third Succession Act which returned both Mary and Elizabeth to the line of succession.