If the race you're timing is not on RunSignUp, you can create it in RaceDay Scoring. You will have the option of publishing the race to RunSignUp when setting it up, or keeping it an offline-only race by not checking this option.
To get started, click the "Manage Races" link from the main landing page, or from the "Select a Race" dropdown.
From this page, click "Create a Race"
Next chose whether or not you'd like to publish this Race to RunSignUp in order to manage your participants online, as well as publish results to the web. Then continue on by filling in the fields shown below.
When filling out this form, be aware that these fields can be updated later, and the start time and end time are not used for scoring purposes.
You can add additional Events here. For instance - if you are scoring a 5k/10k you would want to add the 10k as an additional Event.
After clicking "Create" this Race will be generated and opened up for you.