Aethercrystal porting: why is mine different?

I've watched several youtube vids for help/advise on various things and have noticed some people are able to click on the main city aetherite crystal and port to the small local city crystals. So when I click on the main crystal I do NOT get the option to do and I'm wondering why that is? I had thought maybe they were old vids, but the latest lightening quest vids posted in this forum are the same. Jooz can use big crystals to port to small crystals within the same city.

Have I missed something? Am I doing something wrong? I have to click on small crystals to port to other small crystals. The big crystal does not give me the option.

Click the first option.

well..
what above said... but just noticed that u have to interact "attune" with those small crystal 1st. Whenever u see a small crystal, just interact with it. And also once u interact with all (per city) u get the option to teleport directly into one of the main gates of the city (which i personally love :) )
enjoy eorza..

Yes, it's called the 'aethernet', and is a free mini-teleportation system within each city. Find the small aetherytes scattered at points in each city, and they allow you to travel to and from them and the main aetheryte. Attuning to all the aethernet shards allows you to also use it to teleport directly to outside the city's main gates as well, but this doesn't work in reverse sadly. In any event, after attuning to an aethernet crystal, click on it to teleport to another aethernet crystal, or from the main city's aetheryte, click on it and select 'aethernet' (the top option), and then the location of the aethernet crystal you want to teleport to. :)