For the portal, you need purnge blocks, to make those you have to find purple ore and orange ore which generate below y level 25, mine them with a diamond pickaxe, smelt them into ingots and combine them in a crafting table. You only need four purnge ingots per block. To ignite the portal, you need a flint and purnge, made by combinining a purnge ingot with a flint, the shape of the portal is the same as a nether portal, hope this helps.

Thanks!