The following sentence comes after the one talking about the problem of criticism not being specific enough for big goals:
The sentence says “Instead” because that’s what you could do in place of having one big goal. Instead of having one big idea that criticism can’t be specific with, you can do what’s said in the quote above.
How does separating goals into pieces make criticism more specific? How does separating a goal like “do x and y and z” let criticism be more specific? I think if you talk about each letter as an individual goal then your criticism can point out a specific error.
I think the sentence is connected with the last sentence to say that if you want criticism to be effective then you’re gonna want to separate big goals into pieces. Idk
The sentence provides an alternative to only having a big goal. You as a reader already got a picture in mind of a big goal like “do x and y and z”. Now you can picture separating the goals like “Do x. Do y. Do z.” After that you can see that instead of criticism commenting on one big goal, it could be more specific and comment on individual sentences.