Humans are extremely efficient in rapidly and flexibly converting complex symbolic instructions into novel behaviors. Previous evidence and theoretical models suggest that the implementation of a novel instruction requires the reformatting of its declarative content into an action-oriented code optimized for the execution of the instructed behavior. While neuroimaging research focused on identifying the brain areas involved in such process, its temporal profile and electrophysiological characteristics remain unknown. In the present study, we recorded EEG while we asked participants to either simply maintain declaratively the content of novel S-R mappings for recognition or to proactively prepare for their implementation. By means of time-frequency analyses, we isolated the oscillatory features specifically associated with the proceduralization of the encoded instruction. Before the onset of the implementation target, we observed stronger delta/low-theta activity over frontal electrodes and a significant suppression in mu and beta activity over central electrodes. On the contrary, activity in the alpha band showed no differences between the two tasks. Together, these results support the crucial role attributed to prefrontal regions in orchestrating complex task setting and further extend on it by characterizing the temporal and frequency profile of this process. Moreover, we highlight the critical involvement of motor activity in the proactive preparation for novel instruction implementation.