I'm not sure how else to explain it - it sounds pretty obvious to a native English speaker. Here are some examples of it being used in context:
"This website is launching next Monday - we have seven days to make sure that everything is ready"
"This is a nice hotel. We have two days here before we go on to the next city on our trip".
Thank you! Your explanation is really helpful. We actually say the same in German, but I didn't understand that this sentence is meant like that.