You build your load profile in Connection Establishment inside your test scenario. The load profile describes how many users/connections you want to generate, how fast you want these users/connections to be generated, how long these connections should last, and so forth.
You can assign subnets in the Subnet Selection part. As soon as you have selected a subnet, you will see the available IP address from that subnet and how many IP addresses are used in your test scenario.
User Connection Setup
You define the relation between connections and users in this part. Since a TCP connection is defined by a 4-tuple, that is, source IP, source port, destination IP, and destination port, you can change the number of connections per user using Number of Source Ports, Number of Destination IP Addresses, and Number of Destination Ports.
Connection Establishment Profile
You can add multiple load segment as shown below to build the load profile you want. Each row consists of the number of users, offset time, ramp-up duration, steady duration, ramp-down duration, and time scale.