4DS - Anything but Charting, page-465

It will depend on the conditions of the takeover.

If it is pure cash, then you get cash for your holding at the TO price.
If it is a combined cash/script take over then you get part value in cash and the remainder in stock in the new (possibly foreign) company.

Management may also elect to de list from the ASX and relist on a foreign exchange, in which case 4ds becomes a foreign company (without a take over). Think back to Newscorp (this is an unlikely scenario).

Once a TO is announced you can sell your holding for the current price, which may be more or less than the TO price.
It will be more if the market believes that a better offer will come. It will be less if the market doe not like the conditions of the offer or if there is no chance of a better offer.