Unique ID consist of two parts: parameter part and  interval part. Parameter "offer”is required, others are optional. Along with "offer" parameter, you can add 3 extra parameters.  As per interval section, by the time FuseClick has only“1 day” option as default and it cannot be changed.
Set default Unique ID composition  here “Setup > Setting > Tracking Setting. This rule will be applied by default only for new offers, which are created after this rule has been set.

It is also possible to create different Unique ID rule for specific offers, go to "Offers > Manage Offer > Offer Detail > Tracking” page. Unless you activate Unique ID setting by turning Limit Conversion by Unique ID ON, it's not going to work. (Read more about Limit Conversion by Unique ID)