Choose what reflects your current running stamina combined with your running experience. When you are very experienced, but haven’t run for months for example; please consider starting as an intermediate instead of an advanced.
You can always switch your profile within your training plan. You will notice that a higher experience level will cause the suggested running workouts to become longer and more intense more rapidly. However, you can reach the same duration and intensity of workouts with a beginner profile. It will just take a bit longer because the body is simply less experienced and accustomed to running.
Beginner: You are an absolute beginner or able to run up to 5K
Intermediate: You regularly run 5K to 10K without stopping
Advanced: You can run (half-) marathons and experienced with structured training