I really suggest not using coinbase, they have terrible service and they will sometimes not let you remove your coins from the site. They also have recently stopped people from redeeming their bitcoin if they live in certain states. I suggest using kraken.com and then moving your coins to a paper, hardware or actual wallet on your computer which is what you will be doing with ohm.
If you have coins on coinbase get them off as quickly as possible, many people are seeing a Mt. Gox similarity in their actions.
https://steemit.com/bitcoin/@nickdavison/bitcoin-wallet-coinbase-seizing-american-accounts
RE: The "how to" Guide to The Ohm Wallet.