Responsiveboat: About You section and Polylang

Hello. I have the Responsiveboat theme, I’m working in localhost and I need to make the section “About You” to be translatable with Polylang but I couldn’t do it so far. This section doesn’t appear on the translation strings. I already performed the procedures described in here: https://docs.themeisle.com/article/80-how-to-translate-zerif and tried the procedures in here: https://themeisle.com/forums/topic/zerif-lite-in-two-languages/ in functions.php but introducing those codes, the website becomes inaccessible. If I take them out the website is accessible again.
Could somebody help me, please?
Thank you.
Best regards.