There are lots of ways to make potions, but I wouldn't recommend drinking them unless you're certain that none of the ingredients are toxic or inedible. Personally, I stick to making tinctures, decoctions, or infusions.
Tinctures are alcohol-based (I like 100 proof vodka, it's easy to come by and works well). Other people like rum or pure ethanol, but *don't* use rubbing alcohol. You need a vial of whatever size you want that can be sealed airtight. Put all of the charged herbs in the vial, then pour the alcohol over them. Depending on the strength, you let it sit tightly capped on a sunny window sill for about 5 weeks and swirl or invert the vial each day (don't shake it). Once it's ready, strain the herbs out of it and place the tincture into a new, tinted vial. If it's an edible tincture, I like have a cap with a dropper on it to add how ever many drops are needed to other liquids like water.
Decoctions are really easy to make, but they aren't as strong as tinctures. You basically just put whatever herbs you're using into a pot, and simmer (not boil) it in water for up to five hours, again depending on the strength you want. Then just strain and bottle.
Now, when you meant tea-based, did you mean made like tea (an infusion) or the ingredients including tea leaves? Because infusions are basically tea, if they are water-based, but some people use oils as the base. If using water, you just put the herbs into an airtight container, pour boiling water over them, let it sit for however long is needed for the strength you want, strain, re-bottle. Using oil is the same thing, except you don't heat the oil first, and you let it sit for up to 6 weeks, inverting the bottle each day in the same manner as the tincture. The difference is you don't want an oil-based infusion left in the sun. Keep it in a cabinet.
As far as the specific herbs you're looking for, there is nothing I can do to help you if you can't be more specific about the purpose of the potion.