Relationship problem primary key

Hi all, 

I have a problem trying to relate two tables

Table 1:

Workbook name (unique values)

Resource 1

Resource 2

Resource 3

Resource 4 

Table 2

Activity        Workbook Name 

Activity 1     Resource 1

Activity 2     Resource 1

Activity 2     Resource 2

Activity 2     Resource 3 

I want to relate the table 2 with the table 1 but I can not find the way to create a primary key composed by two columns and that could be related with resources. 

Any idea? any help?

Thank you in advance!!