You'll get a letter detailng how to apply for your entitlement, basically just send the amount of money via BPAY, nothing else to do, no forms etc but it's all detailed in the letter you'll receive in a few weeks/via the online portal.
There's no point sending the money at the start of the period, the 11.5c is valid right through to the 25th of July at which point you can look at the share price and the current state of play in markets, company announcements etc to make a decision whether to take part.
If the share price were 11.5c at that time and you wanted to buy it is better via the offer as there are no brokerage fees and you can sleep well with the deep statisfaction of your money going into the company's coffers
