JuanPabloC

Just arrived in Seoul and I am trying to figure out the public transport system. I have heard the T-money card is the way to go but I am not sure how it works exactly. Can I use it on both the metro and buses? Where do I top it up? Is there a minimum amount I need to load? Also wondering about the metro app - is there a good English-language app for navigation? The system seems very efficient but I want to make sure I am using it correctly.