Evaluation is a bit harder. In academic circles, evaluation means to judge the worth, usually by comparing a thing to some kind of standard. In the case of evaluating an article, that standard would be other article in the same discipline or journal as the one you’re reading. If you are not familiar with those other article it may be hard tom evaluate well. You can, however, do a fairly good job of it by considering the stylistic and structural conventions of other, similar articles. Does this one fit the pattern? Does it measure up to the academic standards of writing, presentation, organization, source citation and such? Sometimes even those questions can be hard to answer but they should be attempted. The answer will give you some ammunition for you critique.