My knowledge of Rpresentation is limited - I used it once or twice for simple things, but before xaringan I usually wound up in powerpoint for presentations. I recall the RStudio overview being good (as pretty much all of theirs are): https://support.rstudio.com/hc/en-us/articles/200486468-Authoring-R-Presentations
Sorry I can't be of more help than to point you at a resource I recall being good, but it's not a tool I use anymore. Hopefully someone else on the forum can help out with any Rpresentation troubleshooting. There was another thread on presentations a few weeks ago that might be helpful: R Presentations