This is the route I am wanting to take. I went for an internal interview for a management position last year and didn’t get the job on the grounds of not having enough leadership experience. To my employer’s credit, when I asked ‘how do I get this experience without being in a management role?’ they gave me a few options, including being a buddy to any work experience/interns/graduates that we hire.
I also got access to the company’s management training programme reading materials. All new managers get sent on the course so it has been good for me to read it.
So if this is a role you’re wanting to go for then I’d speak to your manager (and HR in my case) about how you get that experience. It has definitely worked for me as I have access to quite a few resources now.
I’d also recommend Jerry Weinberg’s ‘Becoming a Technical Leader’ - https://leanpub.com/becomingatechnicalleader
I read it last year but there is a LOT of good information/exercises in there so I’m going to re-read it at some point soon.