How to buy ontology gas?

Can you walk me through the process of buying Ontology Gas? I'm new to the cryptocurrency world and I'm interested in learning how to acquire this particular digital asset. What exchanges support the trading of Ontology Gas? Do I need to have a cryptocurrency wallet already set up in order to purchase it? What are the steps involved in the purchase process? And what are some potential risks or considerations I should keep in mind before investing in Ontology Gas?