Minecraft wiki entry for Survival_with_no_enabled_data_packs, associated text: Once you have created and mined the necessary obsidian for the nether portal, it is now time to open the portal. Although it is impossible to acquire a flint and steel in this world, a nether portal can be activated by any flame, including one spread from neighboring lit blocks and lava. Thus, build your portal by a lava source block, and wait until the random ticks allow the lava fire to spread to the portal and light it. Now you can enter the Nether. When going to the Nether, make sure you have the necessary food, tools, weapons, and armor. Most of these supplies can be acquired by trading with a villager.