Looking for recommendation for deal structure for an IT company

I am considering acquiring a stake in an IT company specializing in Managed Services and Cybersecurity, a company I am well-acquainted with. The current CEO and CIO are also interested in purchasing the company. The owner has proposed that I join as one of five owners. I'm inclined to accept this offer, especially since I have a positive view of the two operators who would become my co-owners.

However, I've never been in a position of holding a minority stake in a company before. Therefore, I'm seeking guidance on several key aspects of structuring such a deal. These include determining the equity stake and investment terms, navigating the board composition, especially in scenarios where I might not secure a board seat, managing operational control and establishing a clear chain of command, ensuring operational transparency, and formulating exit strategies.

I would greatly appreciate any advice on how to approach these elements to safeguard my investment and contribute effectively to the company's success.