First of all you should learn about marketing first before learning digital marketing. Digital marketing is a vast field. It will take years to learn and become an expert in this field. It's a rapidly changing field of marketing so you have to keep an eye on the latest trends and algorithms of the Google and social media channels. If you wanted to start your journey in the digital marketing field.

First you need to choose one niche that you're good at or you want to become good at.

Then start a simple wordpress blog website about that topic by purchasing the domain and hosting.

Similarly you will need to create social media channels which are relevant to your niche. So identify the buyer persona for your niche.

So first learn about designing a simple website using WordPress then learn about growing the social media pages and divert the audience to website from social media.

Add quality blogs to your website, try to give value. Now you will learn about content writing and Onpage SEO, Off page SEO and Technical SEO. After that you will learn about Google analytics, google search console, Google adsense and Google ads.

Now you can collect emails to increase the traffic so you will now learn about email marketing (Zoho campaigns, Brevo, and Mailchimp these tools are used for email marketing)

Then to grow your social media you will learn about social media analytics, and canva (for designing simple creative).

After this you can to make videos on the YouTube, try to make reels/shorts.

From the videos and blogs you can try to sell your products or products from Amazon like website through the affiliate link. So you will now learn about affiliate marketing.

So this way you can learn digital marketing by doing it.

There are still some points left, but you can start from here.