And where do you get a btg address?

This is Testnet.

Please prepare for updates. Join our telegram channel for more info:
https://t.me/btgpool
Telegram group (discuss situation):
https://t.me/BTG_Mining_Pool

Is the BTG alive or not?

no, this is a network test, expect an official announcement in the telegram group.

https://t.me/BTG_Mining_Pool