Summarizing values from different tables

harry6810 , If this a many to many join. then better you do union and summarize

https://www.sqlbi.com/articles/from-sql-to-dax-joining-tables/

example

summarize(union(selectcolumns('Table'1,"Month",'Table'1[Month],"Figure",'Table'1[Figure],"Figure2",0),
selectcolumns('Table'2,"Month",'Table'2[Month],"Figure",0,"Figure2",'Table'2[Figure])),
[Month],"Figure", sum([Figure1]),"Figure2", sum([Figure2]))

or append and aggregate in power query

https://radacad.com/append-vs-merge-in-power-bi-and-power-query

https://radacad.com/power-bi-aggregation-step-1-create-the-aggregated-table