The order doesn't matter much and depends on your measuring equipment and preference. As you'll soon find out, VG are more viscous and more difficult to work with, so I tend to add them last and drip it directly into the final mix (I work with 100% VG nic). Once you put all the ingredient together, just cap it tightly and rinse it under hot water for a few seconds then shake vigorously to obtain a homogenous mixture. Next, just loosen the cap and allow it to steep for a day or two before
vaping it.
As for the menthol crystals, you have to dissolve it into a liquid form using PG or PGA. A thread on how to make menthol drop can be found
here. The ratio and how concentrated depends on your preference (WL mixes it at 10%).
For reference, here's how I did mine (assuming you also purchased it from WL):
1.Empty the 15g bottle of menthol crystal into a small zip-lock bag and crush it with something hard.
2.Stuff roughly half (~7.5g) into a 30ml bottle and fill it with PG all the way to the neck.
3.Shake it vigorously and allow it dissolve, you can use a warm water bath or microwave (5 sec intervals) to speed up the process.
4.This will give you ~20-25% mixture, start with 1 drop to 3ml eliquid and add more if desired.
