It's relatively easy to do.
Do you have >100 TT? If yes, you need training as required (expect 5 hours, depending on the ATO/DTO) followed by skill test with an EASA FE, and some authorities will recognize you the theory as EASA (if certain conditions are met) like AESA Spain.
If your authority requires you to pass the theory, you need to pass Airlaw, HF and Comms.
ELP language assessment
If you are short of 100 hours, depending where you are, you can rent G-reg ACs for hour-building, or fly dual with a FI using EASA ACs (you are not legal to fly solo any EASA-reg)