4DX Chart, page-33

It will depend on how you hold them...

...if you hold on a HIN you should have received a "Chess Holding Statement" from the registries showing the 4DXOA units coming onto the HIN. (83,334 units if you took up the full 30k in the SPP). Around the same time (possibly same envelope maybe) you will have also received a "Notice of Exercise of Options" form explaining how to exercise your 4DXOA. The quickest way to do that and to avoid any paperwork is to arrange a BPay of 0.55c per unit exercised. For each unit exercised you will receive 1 unit 4DX and 1 piggyback option (2yrs/0.75c).

If you have lost the form you will be able to download it from the registry using your HIN by selecting "view single holding". The registry is now MUFG Corporate Markets (au.investorcentre.mpms.mufg.com).

If you instead hold your shares on a custody or wrap platform (eg. if you have an adviser/broker) you will be able to instruct them to exercise the options and they will be able to do that electronically.

You have 30 days after FDA approval (which i suspect will land between last week Aug and last week of Sep) ... so don't leave it too late!