Could you elaborate on the steps involved in selling an Astar token? As a cryptocurrency enthusiast, I'm keen on understanding the process. What are the prerequisites I need to fulfill? Do I need to have a wallet specifically for Astar tokens? Additionally, which exchange platforms support the trading of Astar tokens? Is there a specific fee or tax associated with selling Astar tokens? Furthermore, are there any security measures I should take into consideration to ensure a smooth and secure transaction? I'd appreciate a detailed walkthrough of the selling process.