When you launch the PyCharm software for the first time, you'll see this:
You can select a white theme, which is the default, or change it to a dark theme, Darcula.
Unless you want the Featured Plugins, just click the button Skip Remaining and Set Defaults. PyCharm will start with this screen, the first time you use it:
Click on Create New Project. You'll see this screen:
You can change the untitled to a name of a new project folder. (Or choose a different location from the default.) In the image below, we've typed MyFirstProject as the project folder name on the end.
Expand the Project Interpreter item to take a look at it. You shouldn't need to change anything here. Click Create at the bottom to create your first project.