How do I start the journey to being a PMP?

My question is why specifically PMP?

Project Management is a vast ocean and you can get into it in several ways.

You can do PRINCE2 foundation course to get a foothold into project management.

You can foray into the Agile world through AgilePM , Professional Scrum Master or Certified Scrum Master as well.

Plenty of roads to get into Project Management . But if your mind is made up to go PMP, then

1) First look at a foundation course aligned with PMBOK . I would recommend CAPM. There are plenty of organizations world wide that would do a 2-3 day course on CAPM followed by the exam based on PMBOK.
2) Then with that certification try to get a job/project and use those principles
3) Finally you can apply for a PMP certification, sit the exam and be PMP certified. Mind you the application for PMP exam asks for specific full time experience of several years of directing and managing projects. The exam itself is a practical application of PMBOK principles and I personally studied for 6 months for the exam itself .

Unlearn your preconceived notions on how projects should be managed.
Choose a PM book and secure a PMBOKv6.
Read the book together with the PMBOKv6 to build a foundation. This should also help you unlearn more of your preconceived notions.
Take practice exams - this will give you visibility to your knowledge gaps.
Continue reading and studying focusing on the knowledge gaps.
Enrol to a PMP prep course. This is very helpful as you can work/discuss/brainstorm with people with the same goal. This could again help you fill your knowledge gaps.