I want to know how to make a saving countdown, for example you can skip 1 stage every 15 min but lets say the countdown is at 8 min then if you leave and join back it will still be 8 min
Use datastores to save the amount of time(in seconds) when they leave, then when they join back check if the key “skip_time” in their saved dictionary exists, if it does set the in-game value to it, else set the in-game value to 0. Then if they buy a skip(do not let them by a skip if their skip_time is above 0), set the in-game value to 15*60, run a loop each 1 second to substract the value by 1 until it becomes 0(basically second countdown), then when they leave, and you attempt to save their data(such as levels) also save their “skip_time”.
PS: I assume you use a dictionary to save player data, which seems more efficient, if you only save their levels as a value you could perhaps make a new datastore for skips(although I consider it an expensive solution). If you have questions related to any of the tools that may be useful, you can check Datastores, os, dictionaries, coroutines.