To tell the truth, i know very little about training ringnecks. When Skye came to live with us, he was already eight years and was fully tamed and trained. Ringnecks are not good talkers- in her whole life, Skye has only learnt three words. She's also a very stubborn bird (I suppose most ringnecks are) and will let us know if she doesn't like what we are doin with a hard peck. I', not sure if all ringnecks are like that or is it because Skye was a bit spoilt when she was young. I try to be as firm as possible with her. If she misbehaves (pecks at us or destroys my keyboard) I return her to her cage immediately. She loves being witth me so as far as possible she'll behave herself to avoid being put back into her cage. Most of the time she's a real sweetie who loves covering everyone with beaky kisses.
If the ringneck you have to tame is already grown up, I think you're going to have a tough ime taming him. I think you should start by catching him and holding him in your hands a few times every day. The nore he is handles. the tamer he will get. Just be sure you're waering thick gloves- ringnecks' beaks aren't that dangerous but their bites are very painful!
Good luck with the taming and let me let me know how it goes.