Failure to knit using rmarkdown

I am using RStudio (version 1.2.5019) and have MiKTeX installed to my work laptop. When knitting to PDF using rmarkdown the .TEX file seems to be created ok but I get an error:

Error: LaTeX failed to compile Test-Miktex.tex. See https://yihui.org/tinytex/r/#debugging for debugging tips.

In addition: Warning message:

In system2(..., stdout = if (use_file_stdout()) f1 else FALSE, stderr = f2) :
  '"pdflatex"' not found
Execution halted

No LaTeX installation detected

I assume RStudio does not know where the necessary MiKTeX files are. I have tried adding to the environmental variables without success but I don’t really know what I’m doing. How do I set up RStudio to work with MiKTeX?