How to test any IOS build installed in my iphone using xcode

I have one ios app build developed and shared by someone 3rd part and i have to do events testing(custom events and ecommerce flow) i have installed the app on my iphone now i have to test firebase events but have no idea of IOS testing,as of android we can do that using log cat to check event logs

so can anyone Please guide me how to do IOS event log testing using that build step by step?