Book Down Align Paragraphs

Hi,

I have a bookdown document where i am trying to modify the YAML to right align all the paragraphs. When i run the YAML below in my bookdown document it produces a document where the first page has write aligned all the paragraphs and the second page has moved them somewhat to the left. I am not sure which setting is actually doing this in either my preamble.tex or my _bookdown.yml. Does anyone know how to align all paragraphs to the left? I thought using the line geometry: "left=4cm, right=3cm, top=2.5cm, bottom=2.5cm" would correct it but it appears not to be the case.

Im basing the YAML below off of the blog post here

preamble.tex

\usepackage{booktabs}

index.Rmd

title: 'title '
author: 'Jane Doe'
university: "University"
date: "`r format(Sys.time(), '%d %B, %Y')`"
knit: "bookdown::render_book"
frontmatter: true 
output: 
  bookdown::pdf_book:
    includes:
      in_header: preamble.tex
    keep_tex: yes
    latex_engine: pdflatex
    extra_dependencies: xcolor
fontsize: 11pt
toc-depth: 1
secnumdepth: 1
lof: True
lot: True
site: bookdown::bookdown_site
always_allow_html: yes
documentclass: book
biblio-style: apalike
geometry: "left=4cm, right=3cm, top=2.5cm, bottom=2.5cm"
bibliography: ["references.bib"]

Update [14/09/2019]

An example of the alignment i am trying to change can be found in the template thesisdown more specifically the example on page three and page four. On page three all the text is aligned to the right and on page four it is aligned to the left. My hope was to get everything aligned to the left if possible

Thank you for your time

Hi,

Instead of geometry: "left=4cm, right=3cm, top=2.5cm, bottom=2.5cm, I can replace it with the following geometry: margin=2cm. This made the changes that I needed

Thanks