To map yourdomain.wordpress.com site to your Dynadot domain, please follow these steps:

First, you want to add WordPress name servers to your account.

1. Sign in to your Dynadot account.
2. Select "My Domains" from the left-side menu bar and click "Name Servers" in the drop-down.
3. Click on the "Add Name Server" button.
4. Enter "NS1.WORDPRESS.COM" in the "Name Server" box.
5. Press the "Add Name Server" button.
6. Repeat steps two more times entering "NS2.WORDPRESS.COM" and "NS3.WORDPRESS.COM".

Next, you want to set your domain to use these name servers.

1. Select "My Domains" from the left-side menu bar and click "Manage Domains" in the drop-down.
2. Check the box next to your domain name(s) and click on the "Bulk Action" button.
3. Choose "DNS Settings" from the "Bulk Action" list.
4. On the DNS page, select "Name Servers" from the top drop-down menu.
5. Choose the "Select from your Name Servers" option and select the Wordpress name servers you added.
6. Press the "Save Name Servers" button to save your changes.

Now you want to purchase the domain mapping upgrade through your WordPress dashboard. (NOTE: It costs $12 for this service)

1. Navigate to Store, then Domains in your blog's dashboard.
2. Enter the domain into the form at the top of the page and click the "Add domain to blog" button.
3. You will be prompted to pay for the upgrade and complete the process.

Finally, you want to set your WordPress account to use your domain.

1. Go back to the Store, then Domains page and select the radio button next to the domain you want to use. Click the "Update Primary Domain" button.