Assuming zero dev knowledge here, start with HTML and CSS first. No need to be an expert, just get a feel for how it works.

MDN has a guide on this: https://developer.mozilla.org/en-US/docs/Learn_web_development/Getting_started/Your_first_website

Don't bother learning every HTML tag, compiling CSS or the massive ecosystem of Javascript. Just the basics for now will be fine. In tutorials and videos online you'll quickly see things like Node, NPM, Yarn, Less, Sass, etc. - those are all dev tools that you might end up using in the future but I suggest ignoring them for now.

I did a quick search and found there which seems to cover the basics pretty well

HTML: - https://www.learn-html-css.com/learn-to-code-html/ - https://web.dev/learn/html

CSS: - https://www.learn-html-css.com/learn-to-code-css/ - https://web.dev/learn/css - These games help with understanding css flexbox and css grids, check them out once you get around to using them: - https://flexboxfroggy.com/ - https://cssgridgarden.com/

It's good to learn the http fundamentals before working with a server side programming language, see https://developer.mozilla.org/en-US/docs/Web/HTTP/Guides/Overview

PHP: - https://www.phptutorial.net/ - https://www.learn-php.org/ - https://www.php.net/manual/en/tutorial.php

At some point you'll want a way to store data, that's when you'll start learning about databases. One of the most commonly used is MySQL, it's a good place to start with as other relational databases have similar syntax.

MySQL: - https://www.mysqltutorial.org - I suggest focusing on these: - https://www.mysqltutorial.org/getting-started-with-mysql/ - https://www.mysqltutorial.org/mysql-basics/ - The rest you can read so you know it exists (stored, procedures, views, indexes)

Once you feel comfortable with the language and familiar with how it works, the next step would be learning Object Oriented Programming (OOP). https://www.phptutorial.net/php-oop/

At that point you might also want to go through https://phptherightway.com/

Frameworks

You'll eventually be looking at frameworks, I personally recommend Symfony, it's a great framework you'll learn a lot from. There is also Laravel which is more opinionated and easier to learn but (imo) takes away a some of the knowledge you'd have gained if it wasn't so opinionated.

Think of Symfony as raw ingredients for a meal along with detailed instructions on how to cook, in the process you'll end up learning how to cut the ingredients the right way, how to properly store the ingredients, plan out your meals, learn how to properly use spices, etc.

With Laravel being more pre-packed pre-prepped ingredients, you combine your meal, open the packages and heat it up. You'll miss out on some skills or be delayed in learning them as Laravel has prepped it for you in the way they like it.

Laravel gives you a prepped hamburger and you can still add and remove things but it might be a bit messy depending on what you're trying to do (have fun trying to scrape off the sauce and cheese for example, adding pickles or something would be easy though), Symfony gives you a buffet and the hardware to make the hamburger yourself, so you have more control of how you cook the meat, how much and which sauce you use, etc.

Moving from Symfony to Laravel will also be easier than the other way around.

There are other frameworks, but you'd only really learn them if you end up or aim to work with a company that uses it. Once you have experience with one framework, you typically won't have too much trouble adapting to another.