1997 infiniti i30 no start diagnosis Alternator- Electrical?

My son has a 1997 infiniti i30 and when he came home from
college, he said he thought he needed a new battery as had to jump start the car a few times and the following morning I tried to start it and it would not turn over. I tried to jump start myself and I got clicking and decided to get a new battery as the battery looked like it might me the original but even if not (we purchased from
original owner about 6 mos ago) I thought it was a good purchase. Well unfortunately after installing, the same problem, the car would not start at all.There is electrical, i.e. radio, lights,etc and I just assumed it might then be the alternator. Money is very tight now so thought Id try to diagnosis myself via self troubleshooting, but obviously this vehicle is much differen than my Dodge Caravan Base which I have had success with, but to maje a long stiry short, the car has been sitting it driveway for a few months, and a few weeks ago I went back out and there was no electrical, radio, or anything else. Someone suggested it might be an electrical or computer issue, I read somewhere that in some instances, the security system might block the starter or some scenario like that and I wondered if that might be a possibility. I traded the battery for a new one, as had free replacement, and installed and back to same ole, radio, etc with no sound when trying to start engine, and i decided to check the fuses, but though am a novice with the analog mulimeter I
got I could not get any readings from the inside fuses underbdrivers side dashboard, I was able to get readings from the fuses in the fusible link box under the hood, and all of those fuses were good, but did not know how to access or test thw bigger ones like 30 size that have window, and not sure if I pull those out to test, open the cover (plastic or?) or just look to see if they look burned or separated etc. Can anyone help me troubleshoot this issue and/or give me the tutorial on how to test fuses, maybe via online link, tutorial, as would like to test starter, alternator, and or other applicable items, and would really appreciate your help, thanks!

To see if a fuse is ok when they are connected to power simply check the slits on each side of the top of the fuse with your voltmeter. If you use the ohmmeter function of the meter then remove the fuse from the circuit and place the probes of the meter on each of the contacts. You should see zero ohms if the fuse is good.

Check to make sure that the fuses under the hood are getting power. If they aren’t then you need to check the supply lead from the battery to the distribution panel under the hood. Once that is ok then make sure that power is getting to the fuse panel in the dash when the ignition switch is on. If they don’t get power then you need to check the ignition switch operation.

To understand how starting systems work you can do a search on how things work. All cars use basically the same design to work the starter.

A friend of mine had same car. One day he went to put the key in the car and he turned the key and car cranked (engine turned) but wouldnt catch.
He was a type of person who threw his keys alot, on the table, on the counter etc.
Well it turned out in the end that the key had a chip inside of it, and the constant crashing of the keys ruined the key.
$125.00 later at the dealer he had to get another key and have it programmed to work in the car.
You may want to try the spare key if you have one.
The clicking sound probably was your starter trying to engage the flywheel.
You could also have a starter issue.
Why don’t you just remove the starter and get it tested. Some places will test it for free.
The alternator can also be bencha tested to see if its failing.

You have a starter issue and that has to be addressed first. A battery going dead after sitting around for a couple of months could be normal, especially if there had been several unsuccessful attempts to start it before the sitting around period.

If you still have problems with the battery after installing a new or reman starter, then you will need to check out the alternator.

I’d also be checking the starter next, especially because you say the other electrical stuff works. Any way you can remove it and get it to a car parts place? They can check it there.