How do I start a guild alliance?

As a cryptocurrency and finance professional, I often find myself navigating the complexities of digital economies and networks. But lately, I've been intrigued by the idea of starting a guild alliance. Could you provide some insight on how to embark on this journey? Specifically, I'm interested in knowing the initial steps required to establish a guild alliance, from identifying potential allies to outlining a shared mission and goals. I'm also curious about the challenges one might encounter along the way and how to overcome them. Your expertise in this area would be invaluable in guiding me through this process.