All lights and fans etc comes on but the car doesn't start. Assume, its the battery considering its 4 plus years old.

Have a battery pack to jump start. As with jump starts, red/positive of the jump start battery pack is connected to positive terminal of the car battery. Any suggestions on the negative connection? ( it says connect to any metal part ...ideally non pained) . Thinking of connecting the negative of the battery pack to one of the tie down black square hooks in the trunk?

Any suggestions or tips appreciated

 

Just had to jump mine yesterday. I attached the ground to the metal piece used to secure the spare tire. This worked fine for me.

 

On both my XFs the most convenient spot to earth the negative connection was on the bolt on the side that the battery earth lead is attached to.