Your SIM must be inserted before you can use your tablet.
Remove the holder
Find the opener for the card holder. Insert the opener into the small hole in the card holder
Remove the card holder from your tablet.
Insert your SIM
Turn your SIM so it's aligned with the angled corner of the SIM holder and place your SIM in the SIM holder.
Please note: your tablet only supports nano SIMs.
Slide the card holder into your tablet.