How do I navigate this round-about (South African driver)

Hi

I am new to the UK and will need to navigate this round-about in the next few weeks but have no experience of a round about of this size and shape. Could anyone please explain if I need to be in the middle lane to begin and then where do I change lane if this is required ?

Many thanks
John

https://www.google.co.uk/maps/dir/51...1525325400!3e0