Rename your data columns and define their data type before you use them in a map
Column names are automatically set on data import based on the content of your upload file. If you want to display more readable names in your maps ("Building Name" instead of "bldg_name" for instance) , you need to rename them in your portal.
Check here how to access you attribute table.
Click on View Data:
Change a column name
Click a the name of a column to open the information panel:
Click on the name of the column at the top of the panel to edit it:
Make sure you save your changed with the validation check mark button.
Change a column data type
To change the data type of a column, click on the drop down menu of the data type parameter: