Ann: DOW: Presentation - Offer for Spotless & equity raising, page-79

There is a statutory timeline that needs to be followed, which gives the target a period of time to respond to the offer. SPO will need to prepare a Target's Statement (the corollary of the Bidder's Statement) with a recommendation to shareholders as to what to do. Once that happens, the Offer will open and you can accept into the bid.

To reiterate, the DOW offer is not yet open, and can't until SPO responds with a Target's Statement. At that point DOW will release details on how to accept the offer.

Note - DOW's tactics are quasi-hostile in the sense that they haven't engaged with SPO prior to launching their bid. In the majority of takeovers, you know the exact timetable because it gets agreed with the target. In this case, SPO has [x] weeks (I can't remember the exact number) to prepare it's Target's Statement, which is why DOW can't put a definitive date on the opening of the offer.