LG v20 User Manual page 12

The Basics
10
Step 3. Replace the Back Cover
1. Line up the bottom edge of the back cover with the bottom of the phone.
Then press gently along the bottom edge to start securing the cover.
2. Starting at the bottom edge, press gently up the sides of the cover to
fully secure it.
NOTE Using excessive force may damage the hooks along the inside edges of the back cover.
Instead, when pinching the cover in place, apply slight pressure upward (toward the top
of the phone) to engage the securing hooks.