Acer Aspire T136 Service Manual page 60

Standard Reassembly Process
1. Install the Motherboard Module to the chassis.
1-1. Insert the memory to the Motherboard.
1-2. Install the CPU to the Motherboard socket then click the latch.
1-3. Install the heatsink to the Motherboard.
Click the claw
Revolved the latch to fix heatsink