There is provided a method of creating computer instructions for transforming inbound instances, being instances of a hierarchical inbound data format, into outbound instances, being instances of at least one hierarchical outbound data format, wherein each inbound instance is transformed into zero, one or more outbound instances, the inbound and outbound data formats each having a number of segments arranged in a hierarchical manner, the method using a computing device having at least a processor, a memory, a display device and an input device, and the method including: retrieving from the memory and providing on the display device a number of operation icons each representing at least one operation to be performed on data; and enabling a user of the computing device to select and arrange at least some of the operation icons on the display device.