right formula to include it in conditional format when I need to include many criterias

Select the range B5:AF39 and use the following formula for conditional formatting.

=OR(B$3="Fri",B$3="Sat")

Please find the attached sheet with conditional formatting applied. You can edit the formatting as per your choice. To do so, select the range again --> Conditional Formatting --> Manage Rules --> Select the correct rule from the list --> Edit --> Format --> Set the formatting as per your choice.