Once you are on our checkout screen, and you wish to send your order to a different delivery address. Locate the 'Ship to this address' checkbox. The checkbox will be pre-checked (i.e. there will already be a tick mark in it).
All you need to do is uncheck this checkbox (i.e. click the box so that there is no longer a tick mark in it).
When you uncheck the checkbox a 'Delivery' area will appear at the top of the second column (if viewing on a computer screen) or in the next section below if scrolling down on a tablet or mobile. The 'Delivery' area is there for you to add in different recipient and address details.
Please see the screen shots below which will further assist you.