Well... Firs you have to let new ones grow to maturity. Then I guess you could either crochet/sew/felt your old ones back one. But just growing your news ones out to an age that they are even mature enough to do anything like that with can take another year or so. You can't just take straight hair and attach locks to the bottoms. I guess you could sew loops to the root part of the old locks and make dread falls for now, but that might look silly if the rest of your hair is completely straight.
It's best to just go through the motions again and let the journey start all over. If you still want your old locks attached in a year, There are people on here who did it. You could do a search to find out exactly how it was done