do I need to mix the eliquid i am buying with Glycol.
That depends.
If you're buying the Totally Wicked Eliquid that comes in red bottles with a dropper then no that's already mixed with Glycerine to the nicotine content that you ordered. Just refil your carts direct from the bottle. If you're finding the nicotine content too high you
can dilute it if you want, you can also mix different flavour Eliquids together for a blended taste, I like TW cherry and coffee 18mg mixed.
If you've bought a mixing kit then you need to mix it to your desired content as it comes in 54mg strength which is a bit too strong for almost everyone and will probably give you a banging headache. There's a mixing guide in the pack and great info on the site with a Youtube vid demo.
The nicotine base is also unflavoured so boring to vape unless you add some flavours.