Hello! I am unsure on how to setup a subdomain for my website.. I have tried many ways to no avail. I intend on making it so that a subdomain (eg: cloud.mywebsite.com) link into a document root /var/www/cloud [With an SSL certificate]
I run:

Server version: Apache/2.2.22 (Ubuntu)
Server built:   Jul 15 2016 15:32:34

I already have a apache2 VH setup for my domain:

# mywebsite.com main VH
<VirtualHost *:80>
    ServerName mywebsite.com
    Redirect / https://mywebsite.com
</VirtualHost>
<VirtualHost *:443>
    ServerAdmin webmaster@localhost

    DocumentRoot /var/www
    ServerName mywebsite.com

    SSLEngine on
    SSLCertificateFile /etc/apache2/ssl/mywebsite_com.crt
    SSLCertificateKeyFile /etc/apache2/ssl/mywebsite.com.key
    SSLCertificateChainFile /etc/apache2/ssl/COMODORSAAddTrustCA.crt
    <Directory />
        Options FollowSymLinks
        AllowOverride None
    </Directory>
    <Directory /var/www/>
        Options Indexes FollowSymLinks MultiViews
        AllowOverride All
        Order allow,deny
        allow from all
    </Directory>

    ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
    <Directory "/usr/lib/cgi-bin">
        AllowOverride None
        Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
        Order allow,deny
        Allow from all
    </Directory>

    ErrorLog ${APACHE_LOG_DIR}/error.log

    # Possible values include: debug, info, notice, warn, error, crit,
    # alert, emerg.
    LogLevel warn

    CustomLog ${APACHE_LOG_DIR}/access.log combined

    Alias /doc/ "/usr/share/doc/"
    <Directory "/usr/share/doc/">
        Options Indexes MultiViews FollowSymLinks
        AllowOverride None
        Order deny,allow
        Deny from all
        Allow from 127.0.0.0/255.0.0.0 ::1/128
    </Directory>

</VirtualHost>
# mywebsite.com VH ends here...
# cloud.mywebsite.com subdomain starts here...
<VirtualHost *:80>
    ServerName cloud.mywebsite.com
    Redirect / https://cloud.mywebsite.com
    DocumentRoot /var/www/cloud

</VirtualHost>

My apache2.conf: (I have removed majority of the comment the full config is here)

LockFile ${APACHE_LOCK_DIR}/accept.lock
PidFile ${APACHE_PID_FILE}
Timeout 300
KeepAlive On
MaxKeepAliveRequests 100
KeepAliveTimeout 5

<IfModule mpm_prefork_module>
    StartServers          5
    MinSpareServers       5
    MaxSpareServers      10
    MaxClients          150
    MaxRequestsPerChild   0
</IfModule>

<IfModule mpm_worker_module>
    StartServers          2
    MinSpareThreads      25
    MaxSpareThreads      75 
    ThreadLimit          64
    ThreadsPerChild      25
    MaxClients          150
    MaxRequestsPerChild   0
</IfModule>

<IfModule mpm_event_module>
    StartServers          2
    MinSpareThreads      25
    MaxSpareThreads      75 
    ThreadLimit          64
    ThreadsPerChild      25
    MaxClients          150
    MaxRequestsPerChild   0
</IfModule>

# These need to be set in /etc/apache2/envvars
User ${APACHE_RUN_USER}
Group ${APACHE_RUN_GROUP}

AccessFileName .htaccess

<Files ~ "^\.ht">
    Order allow,deny
    Deny from all
    Satisfy all
</Files>

DefaultType None

HostnameLookups Off

ErrorLog ${APACHE_LOG_DIR}/error.log

LogLevel warn

Include mods-enabled/*.load
Include mods-enabled/*.conf

Include httpd.conf

Include ports.conf


LogFormat "%v:%p %h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" vhost_combined
LogFormat "%h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%h %l %u %t \"%r\" %>s %O" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent

Include conf.d/

# Include the virtual host configurations:
Include sites-available/

Unfortunately.. I have not been able to set up a subdomain leading into one of the directories before. I am hoping to enlighten myself as most of the tutorials/guides online i've seen were quite misleading.

A big thank you in advance.