I use Primal. Not sure what else an app/application can be on a pc(sorry, really a bit of a tech dinosaur with computer language)
I do understand relay a bit better now, thank you. 
I did click on most relays offered in the settings and my newsfeed seems to be getting somewhat more diverse in content, maybe also as I follow more people.. So if I would like to get content on lets say 'knowledge of editable plants and their health benefits' or 'how to prepare and cook chicken properly'so it aint dry', is there a relay for that?, and where do I find that? 🙏