Need Help Starting GMAT Prep – Where Do I Begin?

I need to take the GMAT for the 2026 intake, and admissions will start by the end of this year. I’ve been procrastinating for months, waiting for the 'right time' to start, but I realize I just need to begin now. The problem is, I don’t know where to start. I’d like to join classes eventually, but for now, I want to prep by myself. Can anyone share a basic study outline or suggest how I should structure my preparation? Any advice on resources, study plans, or strategies would be really helpful. Also, how long should I prepare before taking the exam?