How to buy Polkadex?

Could you please provide a step-by-step guide on how to purchase Polkadex tokens? I'm new to the world of cryptocurrency and would appreciate a clear explanation of the process, including any necessary account setups, exchanges to use, and any security precautions I should take. Additionally, is there a minimum investment required to buy Polkadex, and are there any fees associated with the transaction? Thank you in advance for your assistance.