OpenCPN compatible Charts

[fsnew]

I bought two S63 charts from ChartWorld but I have troubles to charge and read them on OpecCPN. I don't know why but the Charts Bar doesn't show the S63 button . According to ChartWorld instructions I have downloaded the attached FTP files and I have put them in a Pi directory on my Raspberry, but I am not able to open the files using any of the buttons available on the Charts bar. I hope not to be obliged to create on my own the S3 Plugin , because the procedure seems to be complex and I am not confident to get a wright result. Could I try a procedure to open the S3 files only using the bar buttons now available without installing a S3 plugin?
Could anyone help me for solving my issue?
I thank you very much,
best regards,

Francesco