Navigate to utilities>KML to BNA and convert your kml file into a bna file

Then create a service area boundary by navigating to draw>service area boundary and save file

Navigate to databases>towers/poles

Choose the option create along streets then click the button create points

For the bounding polygon file point to your service area boundary bna file you created in step 2

For the streets directory point to the folder that contains the file you converted from kml to bna in step 1

Click create

Then click save