Full transparency: This is likely not the most efficient way of doing this, so if an expert shows you a different way, please use their technique. However, this code does get the job done.

Install and load the required packages

Installing

You only need to run this once

install.packages(c("readxl", "stm", "textclean", "tidytext", "tm", 
									"tokenizers"))

Here are the packages you need to run topic modelling and what they do

library(readxl) # read in your excel file with text in it 
library(stm)
library(textclean)
library(tidytext)
library(tm)
library(tokenizers)