Open Drive
Select the file or folder you wish to share
Press the ‘meatballs’
Click Share
Type the name of the person you wish to share with - it should start to auto fill the information for you
Select the person you wish to share with
You can change the access rights for that person if needed. You might not want them to be able to edit the information in the folder, just to view it only
Press the paper aeroplane to send the file/folder
Once the file/folder has been shared you will see two tiny people beside it in Drive to show that it has been shared.