In order to access some ICE-CSIC services such as your email address, CSIC’s intranet and SACO (CSIC’s cloud storage service) you must have a CSIC account.
Between a few days and up to two weeks after signing your contract, you will receive an email from ice_it-services@ice.csic.es informing you that your account has been created and that a temporary password has been assigned. Once you have this information, you must complete the “Mi primer acceso” procedure to activate your account. You can access “Mi primer acceso” here.
In this image you can see translation of the different sections.
Once this process is completed, your should be able to access your account, you can login here to access your mailbox, keep in mind that the username is NOT your email address, is your DNI/NIE/Passport.
Additionally, you can configure Thunderbird as your email client. You can see a detailed guide here.