http://www.opengl-tutorial.org/ is a pretty fantastic resource of learning this stuff.

Don't worry too much about opengl vs direct x vs vulkan. There are underlying principles that apply broadly to both.

Alternatively if you want a book that goes more in depth, but still allows you to take your first steps, opengl programming guide 8th+ edition is good.

Expect it to require some patience no matter what route you take. Graphics programming is finnicky.