You could consider that everything is light, in other words, energy

The energy-light is like an infinite rainbow of shades and densities, similar to when light goes through a prism and splits into rainbow shades

So, something physical, which is dense, is just quite condensed light-energy
An emotion, an blocked area, etc, a thought, all these are just different condensations of light-energy

A light worker then is somebody who entunes into a purer stream of light-energy-consciousness and holds that while simulatenously being present in the midst of a more condensed, more layered, more conflicted with itself, more seemingly obstructed, light-energy-consciousness

A purer stream, lets say just means it's freer, more open, more possibility available, more spontaneity present ... and more entuned with itself, as if all the strands of light in the stream seemed to cooperate, coordinate, balance, support, celebrate each other ... similar to a mountain stream gushing over the rocks and the individual streamlets of water playing with each other and all together forming what we call the 'stream'

This makes it seem more 'alive'

So in a way, light work is simultaneously inviting in more aliveness and/or inviting the constriction to open up to the aliveness within itself, that's possible

You can tune into any pure stream of energy
The 'lineage' of Reiki is an attempt to ensure people are using a certain high quality of stream
But you can entune into other streams

So, if you imagine your stream, your home stream, as a point or place of light emanating out in the cosmos somewhere, maybe from a star system or beyond, a pure stream.

You find the vibration-color-texture-pulse that it has, this is like its energetic signature, how you recognize it.

For light workers this would probably be somewhat visual, but since it's energy, it could be recognized through any of the senses or inner senses, intuition, knowing or through some kind of special communication, through a symbol, any genuine indicator

Then you just ask/allow/invite/open to it coming down through you, let's say through your shoulders/back/arms and flowing gently loving through the person/situation you're working with, gently cleansing, replenishing, revealing, unfolding, harmonizing and releasing ... it pours through and releases out of them

All must be done in a spirit of cooperation, and free will on everybody's part
There are infinite ways to become more free, so you're just making available one way, based on all intuitively feeling it being called for and appropriate in the here-now

When it's done, it will feel done and you free all the connections between yourself, the other person and the stream/source from each other, so everybody goes back to just open freedom, free to choose and to change, into whatever's next

Like a beautiful kiss and letting go

There are several traditions you can study, In addition to Reiki Japan offers many forms of healing touch, the Qi Gong tradition of China, and the western system of Therapeutic Touch are all good things to look at if you are looking for formal training.
The biggest thing I would suggest is, if you have not done so already, that you find a path that fits you, find a teacher you are comfortable with, and ground yourself in knowing that system by learning it in detail.

After you learn a system then you have the understanding to explore other paths.