Here you have some details regarding the back of the laptop. After you got read of the back cover you can access the following:

1. WIFI card - Easy to change / replace There are two cables attached to it. Remove them, then unscrew the screw that holds the card in place and lift gently up - DONE.

2. HDD / SSD. All you have to do is grab and pull the ribbon (as in photo). There are a few extra steps to change it.