First add a Rate Plan after that add Rates, then define country code & country name, , charge per call (this is surcharge), add first billing increment like 60 sec.(this is duration of first call length ), add Rate per minute (this is charge per minute), & at last add slab length like 30 sec.(this duration mean if client disconnect the call within 30 sec. the charges apply only for 30 sec. & if its exceeds from 30 sec. then charges apply for 60 sec.).