Not very difficult at all. It's mostly just figuring out what you want and how to get it to display. Pretty much just clicking through templates.
You don't need to know CSS or any other coding, Like this community, there's a community (mostly regulars here) that's are willing to help out, and the developer himself is great about helping out as well.
He has both a free tier and a paid tier. With the paid tier you get some additional features like theme builder, duo colored icons, and some other things @gslender is the developer and can better explain what all you get on the paid tier (you may want to reach out in the Hubivue Community i linked to above). He has said there will always be a highly functional free tier, and that certain features like the guest dashboards would be always be on that tier.
Another one I use (was my primary until Hubivue came along) is the android only Hubitat Dashboard App
Both apps use maker API, and both are highly customizable. They both have their unique traits , and very responsive developers. I just prefer Hubivue a bit more now. I think it has more functionality and a very nice visual appearance.
One other thing I forgot to point out about Hubivue, is it is cross-platform, Available on Android, Apple Windows and Web.
