Sony ILCE-7S - Manual (Page 39)

2. Insert the memory card.
Ensure that the notched corner is facing in the correct direction.
With the notched corner facing in the direction illustrated, insert the memory card
until it clicks into place.
3. Close the memory card cover.
[19] How to Use Preparing the camera Inserting a memory card (sold separately)
Removing the memory card
How to remove the memory card
1. Open the memory card cover.
2. Make sure that the access lamp (A) is not lit.