How how do I use wildcard subdomains with WordPress multisite?

To start with I’d like to say that this is all new to me I am not a developer and I’m used to working with managed servers but like the idea of a faster server and paying by the month. I have spent all day just getting this far so any help anyone can give me is appreciated.

So far I have installed WordPress by following the directions at https://www.digitalocean.com/community/articles/one-click-install-wordpress-on-ubuntu-14-04-with-digitalocean. This is working correctly.

I can access and edit my files using shiftedit.net and successfully activated multisites using subdomains.

I created a CNAME record using an asterisk thinking thinking this would create a wildcard subdomain then tried to create child blog/site through WordPress. This is not working. So I created an A record using test3 as the hostname and the ip as the ip thing this would create a subdomain which still didn’t work when I created a new child site in Wordpress.

It took me all day to figure out how to get into developer mode on my Chromebook. I managed to create ssh keys to connect securely from my Chromebook to my droplet server and from shiftedit.net to the server. Beyond this I am not comfortable using the command prompt.

It seems that there are a great many of tutorials but they seem to all be geared towards experienced users. If someone knows of a easy to follow step by step tutorial on how to create wildcard subdomains for WordPress Multisite I would appreciate the link.