CVT Transmission

I need to know exactly where and how to put the transmission fluid back into
my car.  I need to put the CVT transmission fluid back into my Suburu
because I think that I drained it instead of my oil. I still have the fluid that I
drained. The code reads that the tranmission fluid is low after I drained it.
The ABS, Control light and the uphill light all came on when I started it, which
confused me; but after buying, home delivered, code reader, I got the code
OBD-II Code P0841; which Google ID'd as SYMPTOMS: Transmission may
not shift properly
Common Problems That Trigger the P0841 Code
Transmission Control Module (TCM) failure
Transmission fluid level is low
Transmission fluid pressure sensor failure
Wiring issue
I drove the car for two miles before I was totally stopped when the battery
died when I stopped to get gas in the car. I hope that I didn't destroy the
transmission!