For BTG, since you didn't have BTC in Coinomi at the time of the snapshot, you need to do the following:
1. Create a BTG wallet in Coinomi, WITHOUT altering the derivation path (our instructions in the link above were for people who had BTC in Coinomi at the time of the snapshot).
2. Get the private key of the BTC address that contained the BTC at the time of the fork. Consult your wallet provider's FAQs on how to do this if you have trouble doing so. Consulting our article for the (near similar) situation of the Bitcoin Cash fork, might help you get your private keys from your wallet provider:
https://coinomi.freshdesk.com/suppor...s-with-coinomi
3. From your new BTG Coinomi wallet's Overview page, click on .../Sweep Wallet, and enter the private key you got at step 2.