How could someone create little text blocks like this with an avatar for the speaker and put it on a wordpress article? Noob here!

It shouldn’t be too difficult, and there’s a few ways you could do it.
If you need static content and use a block theme you can achieve a similar look like this:
– create a group with vertical piling layout
– put the larger quote as first block
– as second block put a group with horizontal alignment
– in the group place the image and a paragraph that will go side by side
– you will have to stylize the blocks, maybe adding a custom class in the editor and targeting it in your CSS

If you want dynamic content the best solution would be creating a custom post type (via code or using a plugin), create the layout you want and include it in the page by a loop block or via custom templates