zu oder nach?
if i say We go to mcdonalds, do i say wir gehen zu Mcdonalds or wir gehen nach Mcdonalds?
well i said it is tricky because there are several words which are used in this context but even so you can't just randomly switch them.
if you go to the hopital you say ich gehe ins (in das) Krankenhaus.
if you are going to school you would say: ich gehe zur Schule or ich gehe in die Schule.
if you go to Mcdonalds you say ich gehe zu Mcdonals. (maybe you could say ins Mcdonals as well but it sounds kind of weird.)
im is not used in context of a destination you only use im if u (or whoever wanted to go) are (or is) there already. since it implies to be inside of something. (im= in dem)
About that I know a joke:
A: Ich geh noch schnell nach Aldi. (I just go to/after Aldi.)
B: ZU Aldi! (To Aldi!)
A: Wat? Schon halb sieben? (What? Is it already half past six?; "Wat" is regional (Rhineland) for "Was")
What you need to know to understand that joke: 1."zu" also means "closed" 2.In former times every shop had to close at half past six pm (Ladenschlusszeit). Nowadays this joke has to be changed, because Aldi is opened until nine.