The cosmic witness is understood as the universal source; omniscient, omni-present, and infinitely guiding remembering. It is not separate from you. Consider these 10 steps to ascertain and sense the presence and of the cosmic witness and what it is not:
1) Awaken to your own ego-created desires that exist at the root of your suffering.
2) Step back from the insatiable ego & illusions you create to reinforce perceived problems.
3) Reflect on underlying reasons for your desires, hopes, fears & attachments that create the above.
4) Notice the nature of ingrained beliefs that prompt you to self-judge and imagine what is not there.
5) Recall cosmic consciousness is the core state that re-aligns you with true nature.
6) Explore why the mind imagines limitation, inadequacy, reasons for insecurity & loneliness.
7) Let go of beliefs which are themselves conditioned mental delusions.
8) Practice forgiveness of self and others then realize reasons for forgiveness are illusion.
9) Recall the feeling of "right action" & be what it is that reinforces who you are.
10) Realize that every choice impacts perceived self and the whole universe.