Setting on foot means to initiate or begin a course of action. Other similar phrases that can be used interchangeably are "starting off," "commencing," "undertaking," "inaugurating," "embarking upon," "launching," and "instigating."
Each phrase conveys the same idea of starting something with determination and purpose. The choice of phrase may depend on the context in which it is used. For example, "undertaking" may be more appropriate in a formal or professional setting, whereas "starting off" may be more informal and suited to a casual conversation.
Regardless of the phrase used, the act of setting something on foot is a significant step towards achieving a goal or objective.