There are many steps used to put chinchillas together. Some are easy to put together, some are not. There is really no "quick" way to put them together. Especially at that age.
1) Put their cages next to each other.
2) Everyday switch which cage each chinchilla is in (this goes on for about a week)
3) The same time you are switching them have them use the same dust bath.
4) After they are switched back and forth for a week take them out to play together. If they don't fight than this is good, but that doesn't mean they will go together.
5) Keep switching them for another 2 weeks, but have them play together. Eventually, they will stop having little fights. If they still fight after 2 weeks then you need to continue this process. When they are fine together continue to step 6.
6) Clean out one of the cages and descent it by using a 1-1 mixture of water and apple cider vinegar.
7) Put the chinchillas in the cage and hope for the best. Have a glove ready incase they fight. A few disagreements is okay, but if they stand on their hind legs and fight this isn't good. Seperate them if they fight.
8) If they fight on step seven then you will have to start all over again to be very careful when you put them together.
Remember that some chinchillas may never go together and some are very easy to put together. It all depends on their personalities.
A helpful website: http://www.chinchillaplanet.com/introducing-two-chinchillas/