Question about harvesting

I'm a newbie with Scrapebox and this might sound stupid, but I don't understand how to scrape a big list of urls at once.

I mean if I use for an example drupal footprints like here:

http://scrapebox-footprints.blogspot.fi/...rints.html

It takes under 1 minute and it says harvester is completed and there are only under 300 urls (no duplicate domains) in the list. If I want to harvest all footprints I have to export not completed keywords to keyword list and start harvesting again and over and over again the same process.

I don't understand how I could scape all those keywords (footprints) at once by clicking start harvesting button at once.

I use 30 semi-private proxies and 100 connections for harvesting and other settings are default setting I guess.

Thank you