You have stargate and you can use 7 symbols to activate it. Every world differs in some way. Different color palette ,or models. Every world is random except 2. Your home planet and Baal's hideout.

You can find NPC that will sell you useful equipment in exchange for Naquadah. Naquadah will drop from some enemies

Because there is small chance that you will stumble upon the Baal's hideout, there is one symbol in chest in each of the planets. Find all 7 and kill the self-proclaimed god.