Add note for pdflatex

@jgbarah Please check this out and see if this note should be added or not

Author: apoorvaanand1998

manuscripts/first.md

@@ -15,4 +15,6 @@ For example, to produce a report about Git data in the standard GrimoireLab enri
    -n GrimoireLab --data-sources git
 ```
 
-The report will be produced as `/tmp/reports/report.pdf`, using `GrimoireLab` as the name of the analyzed project, when presented in the report.
+The report will be produced as `/tmp/reports/report.pdf`, using `GrimoireLab` as the name of the analyzed project, when presented in the report.
+
+> _Note:_ This requires pdflatex to be installed, the instructions for which can be found [here](https://gist.github.com/rain1024/98dd5e2c6c8c28f9ea9d). If you get an error about 'CJKutf8.sty' not being found, check [this](https://tex.stackexchange.com/questions/125843/how-to-install-cjk-font-to-ubuntu-latex) out.