Okay thanks..
The First point to make is that family court orders only apply to the parents not the children. Meaning, it compels each PARENT to abide by the orders ..... In the case of a primary carer, (PC) to make the child available to the other parent at the times specified, and the 'spends time with parent' ( STWP)to return the child to the primary carer at the times specified.
The orders say that the STWP is to have the child each alternate WE after school on Friday and return child to PC at 5PM on the Sunday... It's a little vague in that it doesn't specify pickup and drop off locations, what is to happen if child is not at school etc, but reasonably standard orders ...
When the clause "and (b) such alternate or additional times as may be agreed from time to time" is included it's meant to provide flexibility to the orders if the parents agree to do so. longer stay with the STWP to accommodate a trip away, birthdays and special occasions for example. If no times can be AGREED upon, the DEFAULT position is the first part of that clause, ie, after school till 5PM alternate weekends.
It's not clear if the magistrate is implying that the 15 YO should decide times spent, and then seek agreement from parents.
You say you have only seen the child twice in the last year, was that because the PC was not making the child available. If so, hopefully the orders will be enough to compel the PC to do so and the child is willing.