A fact table is usually designed at a low level of granularity. This means that we need to find the lowest level of information that can be stored in a fact table  e.g., employee performance is a very high level of granularity. Employee_performance_daily and employee_perfomance_weekly can be considered as lower levels of granularity.
The granularity is the lowest level of information stored in the fact table. The depth of the data level is known as granularity. In date dimension, the level could be year, month, quarter, period, week, and day of granularity.
The process consists of the following two steps:
Determining the dimensions that are to be included
Determining the location to find the hierarchy of each dimension of the information
The above factors of determination will be re-sent as per the requirements.