Wrong PhP version for Moodle

I am currently installing Moodle version 3.10.11 on Ubuntu 22.04, The last step for me is going to example.com/moodle/ to complete the install but it only displays the source code which I'll add at the end of this. I'm assuming that I have the wrong version of PHP, which in this case is 8.1. Could someone guide me in finding and installing the correct version of PHP? Also, when I make a phpinfo file, it still only comes up with the source code.

Any help would be greatly appreciated!

Source code from example.com/moodle:

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Moodle frontpage.
 *
 * @package    core
 * @copyright  1999 onwards Martin Dougiamas (http://dougiamas.com)
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

if (!file_exists('./config.php')) {
    header('Location: install.php');
    die;
}

require_once('config.php');
require_once($CFG->dirroot .'/course/lib.php');
require_once($CFG->libdir .'/filelib.php');

redirect_if_major_upgrade_required();

$urlparams = array();
if (!empty($CFG->defaulthomepage) && ($CFG->defaulthomepage == HOMEPAGE_MY) && optional_param('redirect', 1, PARAM_BOOL) === 0) {
    $urlparams['redirect'] = 0;
}
$PAGE->set_url('/', $urlparams);
$PAGE->set_pagelayout('frontpage');
$PAGE->set_other_editing_capability('moodle/course:update');
$PAGE->set_other_editing_capability('moodle/course:manageactivities');
$PAGE->set_other_editing_capability('moodle/course:activityvisibility');

// Prevent caching of this page to stop confusion when changing page after making AJAX changes.
$PAGE->set_cacheable(false);

require_course_login($SITE);

$hasmaintenanceaccess = has_capability('moodle/site:maintenanceaccess', context_system::instance());

// If the site is currently under maintenance, then print a message.
if (!empty($CFG->maintenance_enabled) and !$hasmaintenanceaccess) {
    print_maintenance_message();
}

$hassiteconfig = has_capability('moodle/site:config', context_system::instance());

if ($hassiteconfig && moodle_needs_upgrading()) {
    redirect($CFG->wwwroot .'/'. $CFG->admin .'/index.php');
}

// If site registration needs updating, redirect.
\core\hub\registration::registration_reminder('/index.php');

if (get_home_page() != HOMEPAGE_SITE) {
    // Redirect logged-in users to My Moodle overview if required.
    $redirect = optional_param('redirect', 1, PARAM_BOOL);
    if (optional_param('setdefaulthome', false, PARAM_BOOL)) {
        set_user_preference('user_home_page_preference', HOMEPAGE_SITE);
    } else if (!empty($CFG->defaulthomepage) && ($CFG->defaulthomepage == HOMEPAGE_MY) && $redirect === 1) {
        redirect($CFG->wwwroot .'/my/');
    } else if (!empty($CFG->defaulthomepage) && ($CFG->defaulthomepage == HOMEPAGE_USER)) {
        $frontpagenode = $PAGE->settingsnav->find('frontpage', null);
        if ($frontpagenode) {
            $frontpagenode->add(
                get_string('makethismyhome'),
                new moodle_url('/', array('setdefaulthome' => true)),
                navigation_node::TYPE_SETTING);
        } else {
            $frontpagenode = $PAGE->settingsnav->add(get_string('frontpagesettings'), null, navigation_node::TYPE_SETTING, null);
            $frontpagenode->force_open();
            $frontpagenode->add(get_string('makethismyhome'),
                new moodle_url('/', array('setdefaulthome' => true)),
                navigation_node::TYPE_SETTING);
        }
    }
}

// Trigger event.
course_view(context_course::instance(SITEID));

$PAGE->set_pagetype('site-index');
$PAGE->set_docs_path('');
$editing = $PAGE->user_is_editing();
$PAGE->set_title($SITE->fullname);
$PAGE->set_heading($SITE->fullname);
$courserenderer = $PAGE->get_renderer('core', 'course');
echo $OUTPUT->header();

$siteformatoptions = course_get_format($SITE)->get_format_options();
$modinfo = get_fast_modinfo($SITE);
$modnamesused = $modinfo->get_used_module_names();

// Print Section or custom info.
if (!empty($CFG->customfrontpageinclude)) {
    // Pre-fill some variables that custom front page might use.
    $modnames = get_module_types_names();
    $modnamesplural = get_module_types_names(true);
    $mods = $modinfo->get_cms();

    include($CFG->customfrontpageinclude);

} else if ($siteformatoptions['numsections'] > 0) {
    echo $courserenderer->frontpage_section1();
}
// Include course AJAX.
include_course_ajax($SITE, $modnamesused);

echo $courserenderer->frontpage();

if ($editing && has_capability('moodle/course:create', context_system::instance())) {
    echo $courserenderer->add_new_course_button();
}
echo $OUTPUT->footer();

I'm expecting you to use apache2 as your webserver. To see what version of php you need you can take a look here. Most of the times you will need PHP7.4.

Here is how you install PHP7.4 on ubuntu 22.04:

Install dependencies to add new repositories:
sudo apt install software-properties-common apt-transport-https -y

Add ppa repository from ondrej:
sudo add-apt-repository ppa:ondrej/php -y

Update package information:
sudo apt update

Install PHP 7.4 and modules:
sudo apt install php7.4 php7.4-common libapache2-mod-php7.4 php7.4-cli php7.4-pspell php7.4-curl php7.4-gd php7.4-intl php7.4-mysql php7.4-xml php7.4-xmlrpc php7.4-ldap php7.4-zip php7.4-soap php7.4-mbstring

Restart Apache2:
sudo systemctl restart apache2