Hi there, how do I continue the assault quest. I'm currently on it but I can't click on the church for some reason. Someone said try reinstalling the game. I did but it didn't work. Please help (I'm on mac Btw)

Most likely, the cause was loading a save made automatically after the assault began. Try loading an earlier save. You can look for one in the tab with the letter "A" in the load panel — that's where autosaves are. Or load an earlier manual save of yours.
In the new version, we've already fixed the possibility of such situations.