Interpretation of status lights colours when starting up a new time capsule

Question

Time capsule documentation on the booklet included in the packaging about the light status is relatively uncomplete and leading to confusion when interpreting the colours on the fisrt start up.
The light indeed may not come green at all despite the fact that the Time capsule is already connected to the Internet. It may flash slowly amber and you may have as well the Airport section connected. Consequently the amber flashing light is not only reflecting an Internet connection problem
The status light in fact reports about to main activities 1 the Internet connection status 2 the network status.
Using a home DSL modem to connect the Time Capsule with an ethernet cable, open Airport Utility, waiting a few seconds. One can see two leds on the screen. Top one is for the Internet status and left bottom one for the Network status.
If the Time Capsule flashes amber, it may have a green status led on the Internet connection while having an amber status led on the Network side.
When being on the Airport Utility screen clicking on the Capsule will bring up a comment about the problem, asking to change the parameters of the router.
Choosing the bridge disconnected mode will clear  the problem and the status light of the Capsule will finally turn to green colour. On the Aiport Utility screen both ledswill be then green.

Answer 1

By default, it should use Ethernet if both are available, but if the "service order" in your Network Preferences gets shuffled, it may not.
Be sure it's really using Ethernet (turn WIFI off briefly). 
There's a single, fixed partition on the TC's internal HD -- you can't partition it.
Something is clearly wrong; you should get something like 20-25 GB/hour (overall, with a lot of variation), in that configuration.  See #D2 in Time Machine - Troubleshooting.