How can i add a checkbox filter in the explore dashboard?

Hi Garima,

You should be able to add a checkbox filter by editing the Dashboard and adding a data filter and selecting the checkbox field you wish to add. 
 
More information in our article: Adding a data filter

1. In your dashboard, click Add > Add data filter.
2. On the Choose data filter columns page
   When adding a data filter with a checkbox field, you will have the option to select True and False to filter your dashboard.
3. When you're finished, click Apply. Explore displays the data filter.

 
It will be display like this : 

 
I hope this helps, but don't hesitate to open a ticket with our support team if needed