What if a person has OPEN.EOS on the Bitshares DEX?

As far as I understand (and I'm all new to this) this is not enough. I'm in the same position, I have few OPEN.EOS. I'm planning to create MyEtherWallet address and send open.eos there. Open ledger or someone between charges 0.7 eos for this, robbery if you only have few of them ;-(

I'm still collecting the guides (and courage) for this lol. I don't quite understand why I need to involve metamask. Also I don't know if I need to have some gas/eth for this. I hope not since I have none.