There's very little "wrong" way to do it. It's all about playing with it. Some flavours go well together, other's don't, too many of one type can cancel each other out.
Check recommended percentage of flavouring to use to get an idea, but it does come down to what you'll like.
Some will "steep" in a few days, others can take weeks, some will be best between a range of days and weeks (or months) while others get better with more time.
You can warm your mix a bit at first to stir if you want it easier to mix, but don't use heat as much as possible as it affects the nicotine and some flavours, and keep yourself the amount that you're using out, but for long term storage, put your nicotine in the freezer (it will not freeze) as cold and dark makes your nicotine stay stable longer.
Another note about nicotine, oxygen is bad for it... so try to not have too much air get into the liquid, so as you mix, fill the bottles with just enough space to be able to shake and mix, or use other devices, as long as you get as little air in the liquid as possible. I use a small stirrer (a milk frother type) that I keep low in the liquid and work it, avoiding to grab air as I move it in the liquid.
At 36mg, that could be high enough to be harmful if you are sensitive to nicotine, so don't get it on your skin as much as possible, but since some people actually vape at that level, I wouldn't worry too much, but just a precaution.
Make sure that this is out of children and animals reach at all times.
All basic common sense stuff really.
I would highly recommend, go with single flavours (small bottles/amounts) for you to get a taste of how they are for you.
If you don't have a dripper (RDA) already, it's almost a must-have to test things out.
With these, you get to try the single flavours, and then you can mix a few drops in the dripper and see what you would like to combine.