If you are trying to figure out when someone is going to show up, or when an event is happening, it can get tricky when they say "next week" or "next Friday". Next week can mean any day in the upcoming calendar week. For example, next Wednesday could be in 6 days or as far away as 13 days from now depending on context. If you are not sure which meaning is meant, it is best to check a calendar or ask for clarification as soon as possible.
Another confusion is if they are referring to the weekend. When they are talking about a weekend that is coming, they should say this weekend or this upcoming weekend. It makes more sense to talk about this weekend than the one that is next.
It is also important to know what kind of calendar you are looking at. The standard work week is Monday through Friday, so when someone says next week, they are generally referring to the next Monday through Friday time period. It can still be confusing, especially if you are working different hours than a standard work week, but it is best to check with them if there is any doubt.
If you want to be sure you are understanding when people are referring to the next week, there is an easy hand gesture that can help. It is a U shape that starts with the index finger of your dominant hand sliding forward off the palm of your base hand. Then it curves sharply to the left (if you are right handed).