Over the years I've seen different ideas of what grounding is and different versions of achieving grounding.
Grounding is connection in real time (being here now) with yourself and your surroundings. Your thoughts are not a minute into the future nor a minute into the past. It is also a mini meditation. I have used it in the middle of emotionally charged situations, confusion, tiredness, and many other ways.
I have found similar ones, but the following is my version of a grounding exercise.
Visualize a cylinder opening at the bottom of your feet. On inhale, see love light coming in through the top of your head and negative energy going out through your feet.
Visualize the cylinder coming up to your ankles. Breathe in and fill with love light; on exhale, see negativity flowing out into the earth. Energy manure for the earth.
On each inhale, see the cylinder traveling up each chakra point in the body: ankle, knee, base of pelvis, below belly button, diaphragm, heart, throat, third eye and crown. Continue visualizing each inhale as breathing in love light and each exhale as negativity leaving your body through the arches of your feet.
Once at the crown, allow yourself to breathe in light and exhale anything that is not happening right now.