I want to make a Audiospectrum but I don't know how it works. It is only a Logo(image) which should react to the bass(it should grow/get smaller). After that I want to import it to OBS-Studio.
Hopefull somebody can help me.
After Effects makes video, it's not interactive. I don't know what OBS Studio is or does. If you want to learn about Audio Spectrum use the Search Help field at the top right corner of AE and check out the help files and community resources. There are zillions of ways to do what you are describing in AE so you need to learn the basics first. If you are new start here: Basic AE and use the help files. It will take a while to figure it out.