Hello there @ASpayArt!
Welcome to UE! Since you have already confirmed that the content is installed in your system, the best approach here would be to add the content manually.
First, create a new project (ex. Third Person), even without the starter boxes cheched. Then, once inside the project, go to the Content Browser, right click, and choose “Add Feature or Content Pack”. From there, choose “Starter Content”, and add it to the project.