Make sure to have the two Phillips head screws completely removed before attempting the following steps.

Pressing on the small black plastic area will give you leverage to pull off the motherboard gently.

Do NOT flip the motherboard without first detaching the battery's ribbon. The motherboard will still be connected by a ribbon. Only the battery's ribbon will be detached (Marked by the red arrow in the second photo). Using a flat tool to get underneath the ribbon will lift it up allowing you to flip the motherboard over.

The original battery will most likely be attached to the motherboard. A spudger will be needed to detach the battery from the motherboard. Note: Use caution, gently inserting and lifting as it allows. Use of any sharp or pointed tools can rupture the battery and will cause it to burst.