German beer is relatively easy. Restrictive traditions means that most all breweries brew high quality, but basically the same, beers. You can expect to see a Helles, similar to a Pilsner (you may also see pilsners) which is a "typical" beer, one that inspired Corona, but with a nice malty taste and hoppy (by German standards) smell. You will also see wheat beers, the Hefeweizen is good for people who may not drink much beer, it is light and has a spicy, yeasty, slightly banana taste. You also see some beers described as "Dunkel" which will be darker beers, with roasted malts, and in September/October they will have the Fest beers, a Marzen, with caramel malts, so a rich, slightly sweet taste. If the regular beers prove too heavy, very common is a Radler, especially on a hot day, it is a beer (either a wheat or Helles) mixed half and half with a lemon drink. Half litre beers are common, so don't think you need to order a full liter or Maas.
While you may not go to Oktoberfest, do hit up a beer garden, great fun on a nice day, usually with some snacks and light meals available.
Here is a link with a bit more information, it includes some other styles of beer, but most of those are only available in specific regions. https://germanfoods.org/german-food-facts/german-beer-guide/ You do not mention where all you will be, but if in Cologne for example, then you want to try the Kolsch beer, very light, served in small glasses. Dusseldorf? the Alt beers. Berlin: Then the Berliner Weisse's, maybe with a flavoring.