No electrical power fuses test as negative?

I picked up a 2001 Subaru outback had no
electrical power I ran a jumper wire from the battery
to the fuel pump and the ignition on the interior fuse
box just to get it home. Well now I’m trying to find
the cause of the no power and it’s not the fusible
link or any of the fuses I only have power to the
post on the starter and nowhere else anywhere.
However when I hook my test light to the positive
battery cable and test the fuses interior or exterior it
lights up my test light. Why is it showing that it’s a
ground? Even the cable marked S go into the post
on the alternator it is also testing as a ground? And
I am unable to run my jumper wire to get it started
now since the fuses are testing as a ground it won’t
let me run power to it obviously. Any suggestions
on how to track it down? I am using a multimeter
but not having any luck. :( please help!