The (old) Csita guide is written for previous version of EJBCA and there is now new menu items and commands available:
New menu option to import a PKCS#12 file in the Admin-GUI under Edit Certificate Authorities>Import CA keystore.
The CLI command to import a PKCS#12 file is now called bin/ejbca.sh ca importca
The CLI command to import user certificates is now called bin/ejbca.sh ca importcert
For more information, refer to the Csita guide How-to migrate an OpenSSL-based CA to EJBCA.