Hi Nikita,
I assume you want to create colors going for let's say red (lower value) to green (upper value).
You need to create a new heat map palette.

Create your first color (red)
Click on add swatch, create your second color (orange)
Click again on add swatch, create your third color (yellow)
Click again on add swatch, create your fourth color (green)

Best regards,
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Patrick Neveu
Collaboration Betters The World (CBTW)
IBM Champion
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