Shiny app as package: css & all www/ directory stuff

I'm trying to convert a Shiny app into an R package and I am having trouble with all things regarding the www directory as well as "loose" files.

My shiny app works perfectly but when I try to "package it", it doesn't work.

My shiny app directory:

+---my_shiny
|   +---app.R
|   +---utils.R
|   +---www
|       +---style.css
|       +---icon1.png
|       +---icon2.png
|       +---icon3.png
|       +---font.ttf

My code starts like this:

library(hrbrthemes)
library(tidyverse)
library(plotly)

source(here::here("utils.R"))

theme_set(theme_personalized())
update_geom_defaults("text", list(family = theme_get()$text$family))

ui <- navbarPage(
  "Example",
  id = "navbar",
  theme = "style.css",

Now I down't know how to convert it into a package where I can call myapp::appdemo() and it deploys my app.

+---myapp
|   +---DESCRIPTION
|   +---NAMESPACE  
|   +---R
|       +---appdemo.R
|   +---inst
|       +---shiny/
|           +---app.R
|           +---utils.R
|           +---style.css
|           +---icon1.png
|           +---icon2.png
|           +---icon3.png
|           +---font.ttf

But it doesn't work and I don't know how to make it to.