1996 Discovery new battery won't start

Problem:
While driving the battery light came on the dash. Drove it to autozone to have the old battery checked. Battery was bad so I purchased a new one. Dropped it into the vehicle and now my car won't start. By not starting I mean nothing on the dash lights up, the fuel pump cannot be heard, no relay-click, and the vehicle will not turn over. No power to anything. Just to be sure the new battery was in good shape I unhooked it and took it back into autozone, where I am currently stranded lol, to verify it works.

Could this be the ignition relay? Of the three on the driver's side footwell which is it?

Early today I replaced all of the 02 sensors as there was a check engine light referring to two of the 02 sensors. After that It started right up and drove really well... until the battery light came on.

I know there are a lot of threads on this but some direction would be appreciated.

100 amp alternator fuse is blown and autozone doesn't carry one that large lol.

Sorry for checking back in later.

Tugela - I replaced the battery cables because they were very brittle. The negative cable where it was ground against the frame had a lot of corrosion and the positive was very stiff and made some crackling noises when it was moved. Decided to replace them both with new cables.

German Gruner - I did that exact thing this morning and it was good on the meter.

Using a test light my next thought process was to check to the positive post of the battery going down the positive battery cable to the starter to see if it had power. The test light came on at the other end of the positive cable going to the starter. Then I went on to check if the fuse panel in the engine compartment and the fuse panel in the cab had power. Both did not have power and no fuses or fusible links were blown. Only the 100amp fusible link was burned up in engine compartment fuse panel.

I am scratching my head a little here. Initially, I thought because the 100amp fusible link for the alternator blew that the alternator must also be part of the problem. The old battery was not good and would not hold a charge when it was tested. So, even after I replaced the battery, battery cables and the 100amp fusible link I thought I might see at least an interior dome light go on when any door was opened. I replaced the alternator with a spare that was sent to me by stu454 because perhaps that might help(?). Still nothing.

No power is still being defined as no dash lights, no clicking of relays, no noise from the fuel pump and no power in the cab whatsoever.

Am I missing something really obvious or did I just brick my Discovery by changing the battery? lol!

Turns out it was the connection from the positive lead to the fuse box in the engine compartment. The vehicle starts up and drives. Thank you for all the help!