@bishnu On your previous step you already created a streaming dataset (it's like a table with, for example, 'Date Time', 'Temperature' and 'Wind Speed' fields).
Now, in the Flow, you need to select your workspace, dataset name and table name (table name is 'RealTimeData' always). Once you selected the above you'll see a list of your streaming dataset table fields (created in Power BI Service).
You need to put cursor into each of the fields and assign 'dynamic content' to this field. Dynamic content is what your data connector provides (in your case 'Get current weather' connector provides different weather related variables).
For example, put cursor into the Temperature field and you see pop up window with a list of dynamic content provided by 'Get current weather' connector, find Temperature variable and click on it to add to the field:
It's just to match your dataset fields with data fields provided by the weather connector.
Once you are aware with the list of available weather variables you can go back to Power BI and add additional fields to the data set.
For example, add 'Dewpoint' field to the data set (there is a typo in my field name, it's not a problem because you're going to match Dewpoint variable with Devpoint field manually):
Go back to Flow, reload your flow and you'll see your new Devpoint field: