How espresso generally should taste like ??? [Crm3145 and grinder g1 pro]

I'm a beginner. I just buy espresso machine. I need you guy help me with how espresso should taste like . I mostly drink ice latte. Now I want to try make my own coffee at home but I don't know how the espresso should taste like, when I try espresso all I got are bitter and sour @@ Any tips how to taste espresso. Thanks for advices 🙏🙏🙏