Trustlines with Stablecoin Corp's anchors work the same as any other anchor. They essentially act as an agreement that you trust the issuer of a token before you send them FIAT or crypto assets.
Before attempting to create a trustline and fund your account, please ensure that you have at least 0.5 XLM available to be put in your reserve, otherwise this process will fail.
Once you have the required XLM you will need to go through the deposit/withdrawal button on the top right of the Main StellarX page and follow the instructions to deposit/withdraw. This will automatically open a trustline should one not already be present.
Please always go through the general deposit/withdrawal flow when making deposits/withdrawals to avoid any issues, even if you have already created your trustline with the Stablecoin Corp Anchors.