How to set up Screen Sharing on a Mac for VNC connections.
From the desktop click on the Apple logo at the top left
And then choose System preferences
When the system Preferences page appears click on the Sharing Icon
And on the left hand side select Screen Sharing
On the right hand side it will show the name you will need to use to connect, take a note of this for future reference
Then click on computer settings
And select VNC viewers may control screen with password
Type a password into the box and click on OK
When you have finished you can close down the Sharing dialogue box