Scroll up/Return to top Arrow

Hi,

I have checked the many other posts offered and have managed to solve most of my problems with the answers there, which is great.

But a remaining one that I still have is whether it is possible to have a smooth scroll back to the top arrow show up in the bottom right corner once I have moved anywhere down the page from the top.

Unless I am missing something, I was surprised not to find this as standard on a one page theme. Especially given how great this theme is.

Any help would be appreciated. My site is https://doyouneedawriter.com

Thanks