How exactly does Pre new-52 Alan Scott’s ring work, if he wasn’t recruited by the Guardians? and how did the Silver Age end up tying him to the new Green Lantern mythos?
Scott’s powers and origin are a little confusing, as one can imagine with a character this old. For this I’ll only be talking about pre-52 and not the Earth 2 version whose power comes from The Green.
Thousands of years ago, a mystical “green flame” fell to Earth in ancient China as a meteor. A voice in the flame predicted that it would act three times: once to bring death, once to bring life, and once to bring power. For the first prophecy, a lamp-maker crafted the green metal of the meteor into a lamp. In fear and as punishment for what they thought sacrilege, the local villagers killed him, only to be destroyed by a sudden burst of the green flame. For the second, in modern times, the lamp came into the hands of a patient of a mental institution who fashioned the lamp into a modern lantern. The green flame restored him to sanity and gave him a new life. For the third, by 1940, after having already fulfilled the first two-thirds of this prophecy, the lantern fashioned from the meteoric metal fell into the hands of Alan Scott, a young railroad engineer. Following a railroad bridge collapse, the flame instructs Scott in how to fashion a ring from its metal, to give him fantastic powers as the superhero Green Lantern. He adopts a colorful costume of red, purple, yellow, and brown, setting himself apart from his successors, who wear the standard green. He becomes a crimefighter in his first adventure, defeating the crooks who caused the accident. He also discovers his powers’ weakness to wood when he is bludgeoned with a club. Alan is a founding member of the Justice Society of America, and is its second chairman.
Scott uses his ring to fly, walk through solid objects by “moving through the fourth dimension”, paralyze or blind people temporarily, hypnotize them, create rays of energy, melt metal as with a blowtorch, and cause dangerous objects to glow, among other things. It could also allow him and others to time travel. Occasionally, he uses it to read minds or create solid objects and force fields in the manner usually associated with fellow Green Lantern Hal Jordan.
Which gives you a basic idea. Now, eventually the magic meteor, now known as the Starheart, had its background expanded, even being tied, tangentially, to the much more well known Green Lanterns that work for the Gaurdians.
From DC’s Wiki:
Three and a half billion years ago a humanoid race from the world of Maltus sought to bring order to the stars. An offshoot of the race became known as the Guardians of the Universe. They sought to remove magic from the universe, and laid siege to the necromantic forces of the cosmos. The war was costly on both sides. The last to fall was the powerful Empire of Tears, finally subdued by the Guardians on the tombworld of Ysmault.
After the wars, the stray mystical energies were gathered and bound in an orb called the Starheart. This collective force was hidden in the heart of a star and grew in power and eventually gained self-awareness as the Green Flame of Life. Though the Guardians were powerful, the force of magic was something that could not be contained forever. In preparation for this day, the Starheart willed a small portion of itself to travel through the universe to fulfill its destiny. As it traveled through space, the piece of the Starheart gathered debris over the centuries until in resembled a meteor.
Two thousand years ago, the Starheart fragment had found its way to Earth…”
There’s more, including Scott eventually ‘absorbing’ the Lantern into his body, negating his need to recharge – fun fact, instead of working like a Green Lantern Corps battery it had a set time period of 24 hours, regardless of use – and even losing the ring and channeling power through his hands, but that’s the basics.
For more you can check out the wiki articles more, especially the “Powers and Abilities” section on Wikipedia and the DC wiki on his ‘New Earth’, especially the stuff about the ‘wood flaw’.
Final Fun Fact: In Superman & Batman: Generations it was suggested that early wooden club just passed through because he was inexperienced but because he assumed it was a weakness that became the case, meaning it was all psychological.