Hi Nurul,
what routing protocol are you using? if you use static routes, you can use normal static route for the primary link and floating static for the secondary.
eg.
ip route (for primary link)
ip route (for secondary link)
Note: the Administrative Distance you specify for the secondary link should be greater than 1 as the primary link has the AD of 1 by default.
if you use dynamic routing protocol, you have to consider the metric of that protocol.
HTH, Please rate if it does
Pavan