When a model has no date table, you can build one in DAX. Select New table on the Modeling ribbon and write an expression that returns a table:
Calendar = CALENDAR(DATE(2024, 1, 1), DATE(2025, 12, 31))
CALENDAR returns one column, Date, with every day from the start to the end and no gaps. Gaps are the classic mistake: a calendar that stops early, or one built only from the dates that have sales, breaks time intelligence.
ADDCOLUMNS adds columns calculated for each row. Inside it, [Date] is the date of that row:
ADDCOLUMNS(CALENDAR(...), "Year", YEAR([Date]), "Month", FORMAT([Date], "mmm"))
Then relate the table to the facts: drag Sales[Order Date] onto Calendar[Date] in Model view. A relationship on a date column also lets time intelligence clear the other Calendar filters, as a marked date table does.
Calendar =
ADDCOLUMNS(
CALENDAR(DATE(2024, 1, 1), DATE(2025, 12, 31)),
"Year", YEAR([Date]),
"Month", FORMAT([Date], "mmm"))
Every day of both years, with year and month columns.