Best if you read https://www.moneymorning.com.au/your-complete-guide-to-trading-options-on-the-asx-edx . Please not MUSOA is a bit different. In plain English, you will pay a higher price - closer to the share price but still lower - and you will have time until 20 Jan 2020 either to sell or at any time to convert them to shares by paying 3.5c each. If you would not do either the option will expire and will become worthless and all your capital is lost. That would be insanity and I expect that - depending share price as well as other things like dividends opportunity for shares but not options, of course - that all of them will be converted to shares as it only will cost 3.5c / share.
MUS Price at posting:
15.5¢ Sentiment: Buy Disclosure: Held