I suggest making this post sticky in Installation section :)
So, here we go with setting up wildcard DNS on CPanel.
Step 1. Login to your WHM or CPanel.
If in CPanel - change theme to X3.
Find 'Edit DNS Zone'.
Choose domain you want to enable wildcard DNS for.
Scroll down till you see 'Add New Entries Below this Line'.
You need to put an * in the first box, choose A from drop-down menu, add your server IP address in the next field.
Your IP address should be in one of the other entries in this screen (best bet is to copy the IP from another A record you see above), so just copy-paste it.
In CPanel go to Subdomains menu use * in place of the subdomain prefix/name and add the subdomain.
That's pretty it :)
Hopefully, this helps.