isopods are amoung the easiest pets to care for, (seriously, it takes little to no effort!) here is what you need:
since isopods are tiny, you dont need anything big, a good size is a bit smaller than a laptop, but you can go as big as you want, and they can thrive in much smaller spaces.
substrate is what you put in the tank so they can burrow, some common choices are coco coir, ABG, and sphagnum moss. keep it damp but not wet
isopods have very simple diets, they need leaf litter, you can buy this sanitized online, and calcium. the easiest you can give it to them is through cuttelbone, a high calcium type of bone. its sold in most pet shops.
these are a few of my favorite varieties, along with some popular ones.