When your remote is not performing as expected, the most common solution is to replace the batteries. However, TV remotes come in many shapes and sizes, and depending on the remote you're using, the mechanism to open the battery compartment is different.
Let's have a look at some common mechanisms.
The slide and peel
Push the back cover towards the direction of the triangle point until it becomes loose. Then peel back the back cover.
The clip and tilt
Very common and easily identifiable: you recognise the battery compartment on the back of the remote by the clearly defined lid. Usually, there is a little clip you can hold to remove the cover.
Arrow remotes have a button at the underside of the remote. If you press the arrow, the entire back cover will come loose, revealing the battery compartment.
Slider remotes require you to slide either a part of the back cover or the entire back cover in one direction, possibly marked by a triangle.