To generate a relationship between two characters, roll and choose which die determines the category of the relationship, and which specifies the details. If you get a 6, it is a wildcard, and you can choose whichever option you want, or something entirely different in that category. If you roll doubles, it counts as rolling that number and a 6.
Examples:
1 and 3: Choose the first option of the third category, or the third option of the first category.
2 and 6: Choose the second option of any category, or any option in the second category.
The relationships are intentionally left somewhat vague, and some are not symmetric. It is up to both of you to come up with the best story for how the characters fit together.