[dba-SQLServer] What's in a function

I wrote a quick function that kicks data out in a table format..

example select * from dbo.udfMyFunction ('GUID - 36 char')

which kicks out for example Field1, Field2, Field3 etc...

I wanted to join it to another table...table1 where table1 has Field1 
wich could be used as an input parameter for the function, am I thinking 
of this wrong?

This errors out for me on the input parameter

Select f1.Field1, f1.Field2, t1.Field3 FROM Table1 AS T1
    INNER JOIN dbo.udfFunction1 (T1.Field1)
       ON T1.Field1 = F1.Field1

the error occurs at T1.Field1...

any ideas?

-- 
-Francisco