How to do local seo

Hey guys I hope everyone is doing well. I am new to SEO world and I want to do local SEO for one of my clients. The issue is I do not know how to do Local SEO at all or where to even start. I would appreciate it if anyone could help me or give me an article or a course to learn how to do it.

Main question

The thing that I want to do is that, I want my website to show up in top 3 google map results for different locations(which there is one actual location). For example I want to show up for
online clothing store in new york
online clothing store in los angeles or...

Let's assume that we can ship our product to every other cities. So I hope I could deliver what I mean. I'd appreciate it if you could answer me with practical solutions.

You need GMB's and location-specific URL's. That's the only way to rank in the local 3 pack(Local SEO). Then also boost your main site (for organic SEO)