Copy Ebooks from PC to IPad using Marvin/Calibre

Just been given an old Ipad 2 which Im hoping to use for reading Ebooks

I already have the ebook files on a Windows 10 PC and are loaded in the library in Calibre

I found a WIki on how to use Calibre to transfer the epub files to marvin on an Ipad. The wiki showed how to use a IOS reader application plugin to do this. But now I believe these plugins are defunct

So what is the best new way to transfer the epub files? I have seen mentioned connecting to calibre server and then i see mentioned calibre content server. BUt I dont really understand the difference and what I need to do?

If someone could explain the best way or point me to a good easy to undestand guide, I would be very grateful

Thanks