Firstly, you will need to create an account in the DLT portal by registering your company as an Entity.
After that, you will need to make sure you apply for and get the relevant Sender IDs or Headers registered with the DLT portal.
Once the Sender IDs are approved, you can head on over to Kaleyra's portal and apply for the SenderIDs that have been approved.
To Add the Entity ID for your all your senderIDs in your Kaleyra Account, check out our guide here.
If you want to add Entitiy IDs individually to each senderID check out how to do that here.
The Sender IDs added will be approved at the time of adding and you can start using them right away!