Well, let’s go through this a step at a time.
You need to gather all of your materials, to get oak galls, iron(II) sulfate, and gum Arabic, I recommend buying the iron gall ink making kit from us.
Stir this all together thoroughly and you have made ink. I like to filter it once more through the filter cloth after I have made the ink to get any large clumps out. (this part is extremely messy and not entirely necessary, but it helps smooth out the ink concistency)
It isn’t exactly eyes of newts and the blood of a dragon stewed together under a waxing gibbous moon or anything, but it doesn’t feel far off from that. And this recipe is one of the most straightforward I know of to our modern “follow this recipe, have success making cupcakes” mentality. Frankly, that wasn’t the mentality in the middle ages and renaissance. The mentality was, “here are some guidelines, take these and everything you learned from your master when you apprenticed” and you will succeed. But enough of the history of technical literature and recipes…