You cannot self-certify. You must hire a lab accredited under the CCRA (e.g., in the US: Leidos, Booz Allen; in Europe: TÜV, SGS). The lab will use ISO/IEC 18045 (the methodology PDF) to plan the evaluation.
This lists the from EAL1 to EAL7.
The standard is divided into several parts that work together to define the evaluation process: Part 1: Introduction and General Model iso iec 15408 pdf