Dell EMC E39S Series Installation And Service Manual page 116

NOTE: While installing riser 1B, press the tabs and hold the touch point to align the expansion card riser and the riser
guide pin on the system board.
3. Lower the expansion card riser into place until the expansion card riser connector is fully seated in the connector.
Figure 55. Installing the expansion riser 1A
Figure 56. Installing the expansion riser 1B
116 Installing and removing system components