For 17-Inch Models - Lenovo IdeaPad 3 Hardware Maintenance Manual

Screw specifications
M2.5 x 4
Step 3. Pry up the latches and then remove the lower case.
Figure 4. Pry up the latches and remove the lower case
Go to
https://support.lenovo.com/partslookup
replacement part:
Lower case
For 17–inch models
Make sure the computer has been shut down before servicing the computer.
Step 1. Place the computer upside down on a flat surface.
Number of screws
10
to look up the Lenovo part numbers of the following
.
Chapter 4 Removing a FRU or CRU
29