Intel SE7520JR2 - Manual (Page 29)

Hardware Installations and Upgrades
6. Align the pins of the processor with the socket, and insert the processor into the socket.
✏
NOTE
Make sure the alignment triangle mark and the alignment triangle cutout
align correctly.
TP00764
A
A
B
Figure 7. Inserting Processor
7. Lower the socket lever completely.
TP00765
Figure 8. Closing Socket Lever
Intel® Server Board SE7520JR2 User Guide 29