Newbie - how to launch SDK manager in Linux please?

Please don't laugh at my simple question - I am just trying to follow the instructions on "Getting Started". I run Linux Mint18.3 on my laptop so I have downloaded the Linux SDK manager, and now I am stuck at point 2 "Launch the SDK Manager". 

I navigate to the folders (bin and share), but can't do anything with any of the files inside. How do I "Launch the SDK Manager" please?