Table Relationships and related function

Hi

This is my first time so please be gentle 😊

I haven’t been using Power BI long so sorry if I am being Naïve.

I have a problem where I am trying to get data out of table 3 (see diagram below) and into a new column in table 6.

I have tried Related but that the relationships are not correct.

I have also tried the following but as I need to look at two variables, but again need to bring the second from Table1 to Table3 it isn’t working:

Column =

            VAR SAccount = Table6[Value6]

return

    CALCULATE(

                SELECTEDVALUE(Table3[Value]),

                all(Table6),

                Table3[Value] = SAccount

    )

Any ideas on how I can get the data I need… oh one other thing if I change the relationships, other tables fail.

Any help will be much appreciated

Table Realtionships