To convert to Di2 you need the Di2 brifters, both Di2 derailleurs, wiring harness and battery pack. Installation should be fairly straightforward. Shimano always provides very good installation instruction sheets with their components so just follow the directions carefully. You can continue to use your current 10-speed crank, cassette and chain.

However, this is a VERY EXPENSIVE upgrade. The Di2 four piece group sells for nearly $4000 (yes 4 thousand!) so I'm not sure it's a job for the novice even if it is isn't that difficult mechanically.