@joeglasner I was wanting to clarify the individual aspects involved with this.
.com is a top-level domain(TLD). There is quite a few TLDs. You can find them here, Wikipedia - List of Internet top-level domains
bayareamade part is called a second-level domain.
The second-level domain and the top-level domain combined together is called a domain name in this case, bayareamade.com
A domain name has to be purchased through a domain name registrar(E.G. Namecheap, Go Daddy, HostGator, etc). I assume you already aware of this but I wanted to put what you might already know in concrete terms.
Then there is a subdomain. A subdomain like the name implies is a domain under a higher level domain. The www part of the domain you've given is a subdomain. If you are in control of a domain name you can have as many subdomain as you like / physically possible. You could have sales.bayareamade.com, support.bayareamade.com, forum.bayareamade.com, etc. All without additional payment.
The way you assign these subdomains is by setting up a CNAME through the nameserver provider your domain name is configured to go through.
While every domain registrar has their own nameservers you do not need to use theirs.
Now this is where user choice comes in, you can either choose to use your domain registrars nameserver, digitaloceans nameserver, or a different parties nameserver.
I'll just assume for now it's a choice between your domain registrar and digitalocean's nameservers.
You always set the domain name nameserver through the current registrar of your domain name. To figure out how to set the nameserver on the domain registrar I suggest consulting their help page, as every domain registrar might be different in how they let users configure their domain settings.
If you decide to stay with your domain registrars nameserver that is where the detailed explanation ends as I can only provide a generalized answer on how to configure the DNS Zone.
If you decide to switch your domains nameserver to the nameservers provided and managed by Digital Ocean, go through your domain registrar and manually switch the nameservers to Digital Ocean's nameserver addresses below.
There is a tutorial made by a member of the Digital Ocean community that might possibly help you with this process found here, How to Point to DigitalOcean Nameservers From Common Domain Registrars
After you do this you need to add the domain name and droplet(By selecting your droplet it automatically pulls the IP allocated to it) to the DNS record of the nameserver. This can be found at Digital Ocean Control Panel - DNS
This assigns an "A" record. Which is the most basic DNS record. It assigns the domain name to the IPv4 address(The reason I specified IPv4 is because an IPv6 address is dealt with in another record, subsequently named "AAAA" record, because an IPv6 address(128 bits) is four times the number of bits of an IPv4 address(32 bits), I.E. A*4 = A*A*A*A = AAAA). So that when people try to access your website, the domain name has the IP address linked to it so that DNS can resolve it(This is because people don't automatically cache every A record.)
Remember when I explained that a subdomain is handled by setting a CNAME? This is another type of DNS record like the A record.
After you setup up the initial A record you should see it listed in the DNS Control Panel page now. Click on view. Then click on Add Record.
You should see a variety of records you can set but for now we will be dealing with CNAME.
You should see two fields, Enter Name and Enter Hostname.
In the Name field you can enter one of two types of values. You can explicitly state the CNAME name such as www or you can assign it the wildcard character(In this case it is just a asterisk, * ) this means that no matter the subdomain a user types it resolves to the hostname that you set in the other field instead of just giving a lookup error.
In the hostname field you can set it to your A record by just inputting the @ symbol into the field. In total this all means that you want to set the cname to the hostname set by your A record. I.E. assigning www to bayareamade.com