First of all, make sure you are in Edit mode of your dashboard.
Then find the right sidebar, and click on the Add Text Widget button.
Then, in the Add text widget segment, select Upload and hit Next.
In the next step, select your CSV file. You can also add a widget description if you wish.
The next step is to put in your Widget Title, select the widget size, and select the “Regular Card” option from the drop-down menu.
Don't forget to click submit at the end.
You can also upload a historical CSV or image file, which will be set only for the specific time frame.
NOTE: You can also use markdown for all passive widgets and footers.
Learn all about text widgets here.