creating a repeat pattern

I was shown that if you put an  image or pattern into Photoshop you can copy the image and flip or rotate it to make a repeat pattern. the only reason I could do this fairly easily, was because I had written instructions, that I could refer back too. I know that computers, especially programs like Photoshop, confuse me endlessly. This is why I will have to work on these  skills a lot more before I will be able to do stuff like make repeat patterns without clear instructions.