To open the colour palette in using the Web app, simply follow these steps:
Click on the object you wish to modify.
Select the roller icon to open the texture menu.
From the texture menu, select the 'rectangle' option.
The colour palette will appear, allowing you to select the desired colour for your object.
For visual reference, please refer to the below to see what the color palette looks like:
If you have any questions or need further assistance, please don't hesitate to reach out. We're always here to help.