In a scenario where a Routing Table has multiple equal length (or equal specificity) routes added for the same destination (as opposed to different length routes), the router will automatically add all the routes to the table and load balance between them.
Suppose that R1 has the following configuration to reach the 10.1.0.0 network:
ip route 10.1.0.0 255.255.0.0 10.0.0.2
ip route 10.1.0.0 255.255.0.0 10.0.3.2
Both routes have equal specificity and reach the same destination network, and so all packets will be balanced.
Note
Balancing is not round-robin balancing. Rather, it is an algorithm that ensures traffic to/from a destination always goes down the same path.