Take the ear tip between your thumb and index finger, simply push and twist it over Loop's stem until it can't go any further. A tip for the silicone ear tips: flip the flexible part of the ear tip backward before installing it on Loop's stem.
Grab the Mute in one hand and your earplug in the other. Gently push the Mute towards the center of the Loop. Once inserted, the Mute reduces sound by another 5 dB!