You can now create a new sub-wallet via TrustVaultWeb. If you are unsure on the difference between wallets and sub-wallets, this article may help.
Steps
Log in to TrustVaultWeb using your email and PIN
Your existing sub-wallets will load as below

Click on the "+ Create Sub-Wallet" button
The dialog below will appear

Select the Wallet that this new sub-wallet will be added to by using the drop down

If you only have a single wallet you will not be able to select anything else
Remember: The wallet defines the policy (who can sign a transaction), so select the wallet that matches your signing requirements.
Please reach out the [email protected] if you cannot remember the policies defined in each wallet
Click "Create Sub-Wallet" and if all goes well your new sub-wallet will appear and be active immediately