I find the overwhelming part for us comes with a huge sheet of paper with all kinds of writing, designs, or math on it. Cut out just the portion of the map she needs to limit unnecessary stimulation. Like just the Western states or the Middle East kind of thing.
Set a timer for a very short amount of time and just reassure her that when it goes off, you are done. No stresses, no worries, you will just finish the next time. We usually study the map for about 3-5 minutes and then take about 5-7 minutes to label, and about 5 more to double check. So about 10-15 minutes once a week.
Since you are just starting this here are some other ideas to make this into more fun and not just another chore:
You could make two color copies of the map. Cut one into the individual countries (or states) and let her match them up that way. One could even be blank, and one could have the names on the countries or labels. You could even blow the size up to make it easier.
You can read the country list off and she can locate it, first on the cut out labeled map and eventually on an unlabeled map.
You can create another matching game by using just the labels and letting her match those to the countries.
Keep it very short and quick. Remember to quietly play classical music in the background to help her brain stay calm. 😉