We usually picture instructions as a vertical numbered list, and most are, but the right structure depends on how the steps relate to one another:
I haven't really considered the structure of lists before reading this section. I have always considered lists that weren't numbered to be harder to follow because I like being able to check things off as I go. However, this makes me realize that different structured lists actually give more freedom and flexibility to complete steps in whatever way is best for oneself. So, in some cases, if a numbered list were provided, it may make the reader think they have to follow a specific order when a different order may be better for them.