You can access grading a journal through various paths, such as the activity stream, the gradebook, or the journal itself within the course body by clicking the Grades and Participation tab. Then, click the name of one of the students and read their journal entries.

You can grade by adding the score in the pill, and the feedback in the speech bubble icon.

If the journal has an associated rubric, clicking on the pill will open the panel where you can grade using the rubric. Select each of the options, add feedback, and close the panel.