"How the load balancing will work?"
As the others have noted, by default, routed load balancing will determine which egress next hop a particular flow will be directed to use. Such load balancing does not, by default, take into consideration actual port usage. I.e. it's possible flows can be directed to an already busy port while another port goes unused.
Also, by default, static routing and dynamic routing protocols that support ECMP will only balance across a fixed number of next hops, which, usually, can be changed, if needed. (NB: the typical default value was 4. BGP, though, I recall defaults with a value of only 1.)
For your static routes, for same destination, if cost is the same, router should load balance across them, within the limitations noted above.
"Can someone help how cef do balancing?"
CEF load balancing, is, more-or-less, "automatic" if CEF is doing the route lookup for forwarding. As, generally, on most, if not all, Cisco recent platforms doing routing, CEF processing is the default.
One possible option with CEF is setting load balancing per packet. This generally results in a very equal load split across all the egress paths, but can often be detrimental to traffic as many flows do not well tolerate out-of-sequence packets. (NB: yes, IP and even TCP might be argued that maintaining packet sequence shouldn't matter, but often it does.)
As explained by Giuseppe, CEF load balancing is deterministic. I.e. a flow with one set of attributes will always be sent the same way. However, some routed load balancing, I recall, such as processed switched, uses a round robin approach.
