Notarised documents

I am applying for Z type and my family for S1, from UK. I need kinship certificates. My sons birth certificates are from UK, do I need to notarise them? My marriage certificate is from Poland, do I need certified translation and to notarise it as well?

I also need them validated by the embassy.. Do I need to validate it before I apply or is this part of the visa application process?! I am really confused!

Emilia