Currently, RAI holders can port their tokens to Fantom RAI using the Multichain.xyz bridge. RAI holders should keep in mind that they need to get FTM first in order to send transactions on Fantom. One way to get FTM is on Sushiswap and then use Multichain.xyz to transfer your Ethereum FTM to Fantom FTM.
Once you have FTM and RAI on the Fantom chain, you should also make sure you have Fantom set up in Metamask (or any other wallet you're using).