They sign up to go cardless via a link you send them (to fill in there details)
once cleaned you log into your go cardless account and manually request their payment, they get an email saying you have done so and in approx 7 days it is taken from them and landed in your bank account.
with cleaner planner, you upload your days worksheets and then click on "start go cardless" from cleaner planner and the process is started for you.
simple