Years ago I had no clue what "atonement" meant, other than being able to quote the Course as saying "nothing happened". This was more or less meaningless to me.
I went about my efforts at "forgiveness" and made some headway but it wasn't until recently that I started to realize just how important the Atonement is.
If you were to do nothing else other than to accept the Atonement, that would be all you need to do. It encapsulates all of forgiveness within it. It shares the same mind of Holy Spirit that forgiveness shares.
Previously I was not really "accepting" that nothing had happened. I tried to tell myself "this hasn't really happened", but it would seem fake and not believable. It didn't even seem especially important or powerful or capable of helping very much - just one more handy phrase to throw at the illusion of being attacked by the world to try to make it go away.
But the atonement IS the cure. It IS salvation. It IS the state of mind in which all has been forgiven and undone. It IS a reflection of your true nature and your innocence. In it ,your innocence is guaranteed and expressed. It is the light which shines away all darkness. It is the beacon of truth and the source of extending miracles as an expression of love.
I could not accept it before because I didn't really know what role it was supposed to play other than some intellectual fact about how none of this happened. I just couldn't accept that nothing had happened. Too much was tied up in illusions seeming to be real. I was too much in belief that I was dealing with a real world with real problems. Even after "doing a forgiveness" I would not be accepting the atonement, not really actually convinced of it or able to genuinely ACCEPT that it was true. And to experience it.
But we must get ourselves into the Atonement if we are to be free of the ego, free of illusions, and free of death. It's not an optional thing. It's MAJOR. It's the doorway home.
The secret to salvation, or the key to salvation, is said to be that "you are doing this to yourself". That concept is like a key that opens the door, because it reveals to you a way to access the Atonement. But it is itself not the Atonement. As an analogy, it is the key, which helps us to access the Atonement, but the Atonement itself is what lies on the other side of the door that the key opens.
Until we can get our mind to the place where we BELIEVE that fear is not real, guilt is not real, sin is not real, separation is not real, and REMEMBER that in God's view we are still completely innocent and MUST be forgiven and lovable/worthy of God, only then are we able to actually ACCEPT, and agree with, and align ourselves with, what the Atonement claims is true.
Only then can we even see, accept, or experience, that all the illusions we thought had really happened did not really happen (due to their unreality), and that therefore we ARE still as God created us. We have to take forgiveness all the way to this truth in order to complete the process and gain access TO a state of forgiveness, in which we and others are seen as FORGIVEN, having done nothing at all. Literally. That literally nothing happened in reality.
Then we will be WILLING to accept and receive God's love again, and share and extend it to others as miracles.