To use the new VET token on VeChainThor you need to swap your current VEN to the new VET. The easiest method to do this is will be to use an exchange. Simply move your VEN to a supporting exchange (like Binance) when instructed to, and around mid-July they will perform the technical stuff for you. You will end up with the new VET coin.
During this swap process the VeChain token will be splitting at a ratio of 1:100. So for every current token you have, you will get 100x new VET tokens.
By staking (storing) your VET in the official wallet after the token swap, you will generate the secondary token known as VeThor (VTHO). VeThor generates at a base rate currently of 0.000432 per VET token, per day.