Can't update

Hi! 

So i got an e-mail from my hosting provider that there is a critical vulnerability due to FPD. I checked my wordpress dashboard for updates, but i don't see any  other than the warning about the vulnerability.

Then I found out that the installed version I have is 6.2.0, and after a bit of research I figured it's ancient and there is new versions up to 6.4.3. I tried updating through the Envato Market-plugin, but when i click the install button, it says that the installation failed. 

I'm not the one who set up the FPD in my company and I find it rather complicated, so please if anyone knows how to fix this, then explain it like i'm 5 years old. 

Thank you in advance! :)