Need a reference to learn to Use the new Blocks

I’m thoroughly frustrated with “Blocks”.
I wanted to add text below a left aligned image and every time I tried a new block pops up that runs thru the image. I even tried adding HTML linefeeds but a new block popped in over my image again anyway. I CAN find seemingly useless things like the “Block Manager” that apparently allows one to select or deselect from a list of the important things like photo galleries but I can NOT find how to INSERT them into my blocks. When I am in a block I can select “Image” or “Add Media & Text” unfortunately BOTH options bring up exactly the same display of images and my pdfs (text documents) are not included.

I don’t know if it’s all me or if the entire “Block” format is just flaky. Probably a combination of both.

Is there ANY kind of instructions available written or video that explain how to function with this limitation of “Blocks”? I have nothing again educating myself but please give me the information I need to be able to put these things to use.
Any assistance would be greatly appreciated!