First off, I’d suggest using each of the individual pheros you want to composite separately to get an idea of what it does.
Then after finding what pheros and what doses work best for you, decide what you would want in a mix. What do you want it to accomplish. (You may find that your first time out of the gate you would be more comfortable just compositing a mix from someone elses recipe such as Steve’s ICM mixes.)
You will want to buy the pheros at a strength significantly stronger than the amount you want to use in the mix. (For example, if you want something at 12.5mcg in a composite you’ll want to buy it at 25 or higher so that when it gets diluted it isn’t in too low of a concentration).
I’d also highly suggest nbully’s calculator. It works VERY well to figure out all the ratios. Mix Calculator 6.0 : More features
For the most part it is trial and error. Any supplies you need for mixing (such as pipettes) can be found here. Just remember that their is no guarantee connected with the Advanced section pheros. I’ve crashed and burned on quite a few mixes before finding ones that work great for me.
Good luck and happy testing! 