I REALLY HATE HUAWEIs PULL TABS! (Just wanted to get that out my system)

Peel back tab 1 and 2 until they are no longer in contact with the battery

Peel back tab 3 and lift up.

This in theory lifts the battery, however, the adhesive holding the battery in is very strong.

You must be patient and careful so as not to deform the battery.

You may need to use a pick under tab 3 to leverage the battery out.