My suggestion would be to just follow a few stamp companies and card-makers on IG and YT. Those won't necessarily be for "beginners", but you will get an idea of the style you like. Then see what products and tools they are using.
Scrapbook(dot)com may have some beginner type classes.
I see you're in South Africa so I'm assuming you may have limited access to supplies. For basics you might want check out Big Picture Classes as well as the other places people have suggested.
You might want to check out the card kits from Simon Says Stamp or Hero Arts or Love From Lizi and the corresponding "10 cards 1 kit" videos on YouTube. That will give you a pretty good guide to how to use one kit to create a lot of different designs. Lots of people are making 10 card videos these days.
Kristie Marcotte has some good ideas on her blog and YT which might be helpful if you like using patterned paper. She has a tutorial on how to turn one 6x6 pad into 30+ cards which might be a good gateway into the craft. It's definitely one of the more cost effective ways to make lots of fun cards. I regularly turn one 6x6 pad and a package of die cuts into a stack of 35 odd cards.
Some people to search for on YouTube are Simon Hurley, Vicky Papaioannou, Card Cutups, Jess Crafts, and Justine Hovey.
Cathy Zielske just started cardmaking last year - her blog is good to follow, or watch her videos - you can just search for the card-making ones specifically. I think she's a great teacher, and very practical and judicious in the supplies she buys and/or recommends.
Otherwise, this thread gives all of the same suggestions I would - scrapbook.com free classes, Online Card Classes paid classes, etc. Oh, also Inklipse (Simon Hurley) on YouTube has tons of great beginner videos.
Cards and Coffeetime on youtube does a lot of 10 Cards One Kit videos. You can go back to her earliest videos and watch her evolution as a card maker. Her designs are doable for a beginner, and are pretty.
Also, as others have said, Jennifer McGuire and Vicky P. Jennifer McGuire's favorite things videos from the last couple of years have good tips even if you do not need the product reccomendations. Her how-to videos have lots of general tips even if you do not like the particular card featured in each video.