EXCEL: I need to populate on a weekly plan sheet in column G 1 :G 48 etc

EXCEL: I need to populate on a weekly plan sheet in column G$1$:G$\mathrm{48}$ etc the names from the roster sheet Dec, Jan etc where if the N $($Night$),$ or D$($Day$)$ next to their name on the roster sheet, it appears in the weekly plan sheet in column G corresponding with the correct date. The names on the roster sheet are in column B$8$:B$\mathrm{48}$ etc. And the N and D are filled in from G$5$:AK$\mathrm{56}$ according to shift pattern and under the date and day which are G$2$:AK$\mathrm{3.}$ I am currently using this formula $=$IFS$($Dec$!$M$\mathrm{40}="$D$",$Dec!B$\mathrm{40},$Dec!M$\mathrm{40}=$"OTD",Dec!B$\mathrm{40})$ which does populate the name, however this way doesn't automatically populate for each day. I have to manaully change M$\mathrm{40}$ to N$\mathrm{40}$ to change the date from the $7$th to the $8$th for example.