Can you tell me what kind of bonsai tree this is please and how to best care...
This is a Ficus - probably "benjamina". This tree can become quite large and thick when growing in its native areas, but is commonly kept as a house plant, or small tree indoors here, in the north.
There are many instructional web pages and videos on the web that explain how to create and care for bonsai plants. This process can be considered an art form, and can take years of practice to perfect, but every master started learning with one plant, so you may find a new hobby and create some long-lived beauties to past on.
Here are a couple of links to get you started:
I hope this is helpful...have fun with your new project and best of luck!