Fixes for Self Assigned IP Ineffective

Thanks. I understand you are using a "wireless ISP". Those services are notoriously poor.

Might it be this one: https://www.yelp.com/biz/instaconnect-davis?

Since the router has to be working and connected for them to use it at all, is it a matter of a problem between the router and my computer?

Yes it is, but that knowledge isn't very useful because the ISP's equipment isn't communicating with your Mac.

You are not doing anything wrong with your Mac; in fact you should probably revert the changes you made. Create another "network location" and leave it with its default settings, unless you have specific instructions from the ISP. Solving this problem will require contacting them.

The network that Mac is connected to (instaconnect) has no IP address — it's blank. It has all the indications of a router that is not connected to the Internet and is not configured to distribute IP addresses.

I suspect "instaconnect" is not the wireless network you need. Contact whoever is responsible for providing Internet service for your apartment.

Now that I think about it, I had one of those services a long time ago. It was just as bad as those reviews state. Worse than dialup, which was the only other option at the time.

The helpful bit of knowledge I recall was that the "wireless ISP" needs to know the IP address of the local router you're using — which is not appearing in your screenshot. The reason for that is they need to know who to bill for their service.

Then, the router itself is probably configured to communicate with only specified devices, for the same reason. Your Mac is not one of them.

In any case you will need to contact that ISP.

I think you'll be much happier with a different service.