Nether Portal spawn Minecraft somewhere else?

My question is that you can spawn the Nether Portal in the underworld where else because the current one is in a bad position and I would like a different position for it far away from the old one but without me the other portal in the upper world where else to place, how and how? I'm grateful for a quick answer😊.

Well nether portals you build with obsidian

5 blocks high, 4 blocks long / wide, the interior must be free and with a lighter you click on an inner obsidian block.

One block in the upper world corresponds to 8 blocks in the nether. So go to the position in the nether where you want and divide the coordinates by 8 and simply build a nether portal at the coordinates. As far as I know

Or it was the other way around 8 Oberwelt blocks = 1 Nether block I'm not sure, just try creative in the single player