If you already have a second color that complements your primary color feel, then you're done! But if you need help choosing one, read on,
Step 1.
Go to:
Step 2.
Click Custom.
Step 3.
Input your primary color where it says Hex Color.
Step 4.
Look at the Primary Dark section to see your secondary color.
Input the generated color into VolunteerStudio to see how it looks.
Step 1.
Step 2.
Input your primary color where it says Pick a Color.
Step 3.
Click the first bubble where it says Pick a Harmony.
Step 4.
Input the generated color into VolunteerStudio to see how it looks. If you aren't satisfied, pick a new harmony.