Having a problem wit the last step of HSTWB Installer

I am running v 1.5ee on Pi 4b and was trying to get this automated mechanism for installation to work. I have manually assembled all the components and run the preliminary scripts. when I try to run the install.sh file I get an error " ERROR ./hstwb-installer/launcher/amibian/install.sh: line 12: dialog: command not found" This happens if I run it from the Denibian terminal or after logging out at that prompt. The file says this: (error command Bolded). I am not sure even what language this script it in? What am I missing that prevents this from running????

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#!/bin/bash -e

# HstWB Installer Install

# -----------------------

# Author: Henrik Noerfjand Stengaard

# Date: 2020-01-01

#

# A bash script to install HstWB Installer launcher for Amibian.

# show install dialog

dialog --clear --stdout \

--title "Install HstWB Installer" \

--yesno "Do you want to install HstWB Installer launcher?" 0 0

# exit, if no is selected

if [ $? -ne 0 ]; then

exit

fi

# create backup of profile, if it doesn't exist

if [ -f ~/.profile -a ! -f ~/.profile_backup ]; then

cp ~/.profile ~/.profile_backup

fi

# create hstwb installer profile, if it doesn't exist

if [ ! -d ~/.hstwb-installer ]; then

mkdir ~/.hstwb-installer

fi

# get root directories

INSTALLROOT="$(dirname "$(readlink -fm "$0")")"

HSTWBINSTALLERROOT="$(dirname "$(dirname "$INSTALLROOT")")"

# update or create hstwb installer config.sh

if [ -f ~/.hstwb-installer/config.sh ]; then

sed -e "s/^\(export HSTWBINSTALLERROOT=\).*/\1\"$(echo "$HSTWBINSTALLERROOT" | sed -e "s/\//\\\\\//g")\"/g" ~/.hstwb-installer/config.sh >~/.hstwb-installer/_config.sh

mv -f ~/.hstwb-installer/_config.sh ~/.hstwb-installer/config.sh

else

echo "#!/bin/bash -e" >~/.hstwb-installer/config.sh

echo "export HSTWBINSTALLERROOT=\"$HSTWBINSTALLERROOT\"" >>~/.hstwb-installer/config.sh

echo "export HSTWBINSTALLERBOOT=\"emulator\"" >>~/.hstwb-installer/config.sh

fi

chmod +x ~/.hstwb-installer/config.sh

# create first time use trigger

touch ~/.hstwb-installer/.first-time-use

# install hstwb bin

cp -f "$INSTALLROOT/hstwb.sh" "/usr/local/bin/hstwb"

chmod +x "/usr/local/bin/hstwb"

# copy hstwb installer profile

cp "$INSTALLROOT/install/boot/.profile" ~/.profile

# copy hstwb installer menu files

cp -r "$INSTALLROOT/install/menu_files" ~/.hstwb-installer

# add hstwb to amibian menu

if [ "$(grep -i "cat ~/.hstwb-installer/menu_files/hstwb" /usr/local/bin/menu)" == "" ]; then

echo "cat ~/.hstwb-installer/menu_files/hstwb" >>/usr/local/bin/menu

fi

# copy amiberry configs

cp -R "$HSTWBINSTALLERROOT/emulators/amiberry/configs/." ~/amibian/amiberry/conf/

# copy chips uae4arm configs

cp -R "$HSTWBINSTALLERROOT/emulators/chips_uae4arm/configs/." ~/amibian/chips_uae4arm/conf/

# show install dialog

dialog --clear --stdout \

--title "Success" \

--yesno "Successfully installed HstWB Installer. For first time use Amibian should be rebooted. Do you want to reboot now?" 0 0

# reboot, if yes is selected

if [ $? -eq 0 ]; then

reboot

fi