Negative weight training?

am I supposed to do positive weight training sets first to warm up and on my last set do negative training. And how long should I wait before training again? An example would be nice.

There's no set rule on negative's. But they are extremely stressful and should be used sparingly. Most of the time, the positive-pause-negative reps will get the job done. Negatives can help you get beyond a plateau, should you have one.

You should wait at least 3 days to one week before training again.