By the time you're truly ready to learn the six ball fountain, you probably do not need a tutorial to teach you how. However, if you have some trouble you cannot figure out, you can follow these steps and execises. Like the 5 ball cascade, it takes a dedicated juggler to master the 6 ball Fountain.
Three in one hand
So we will have to start off with 3 in one hand. If you're struggling, try tossing higher to give yourself more time and build down to lower throws as you get more comfortable. Make sure you're consistent and able to average at least roughly 10 catches with both hands before moving on to flashing.
When you start practicing the actual 6 ball pattern, most jugglers find it useful to practice a flash first. So you're objective here is to toss and catch all 6 balls. Practice flashing thoroughly, your choice if you want to go synchronous or asynchronous first. Take your time to focus on this step! It will teach you the basics for when you want to add more throws. When flashing, make sure that your balls are not crossing, and are staying on one side. Concentrate on your timing but not too much, it doesn't have to be perfect.
Progressing to more throws
When you are comfortable with flashing 6 balls, it's time to add in more throws. Some jugglers say that you should add only one or two throws to your flash and stop, while others argue that you should just juggle the pattern for as long as you can. I would recommend you just stop when your pattern becomes unstable. The first problem you will probably encounter is that tosses from different hands start crossing over each other.
The six ball Fountain is not very complicated, but very hard to learn. It will likely take longer than for the five ball cascade, but not that much. There's nothing more to say than practice!(especialy your flashes!). Good luck.