Ask about report from Validator.w3

Ask about report from Validator.w3

Hi team of Validator.w3,
Hope you are well in this time before Xmas.

I have a report with where there are many errors and I would like to know,
which error is important and which not so much. Could you help me or
recommend me to someone?
It is about this report
https://validator.w3.org/nu/?doc=http%3A%2F%2Fwww.galafashion.cz%2Frukavice-damske-bggf0017%2F

Thank you for you time and have a nice holiday
Bests
Tomáš