In freeskating, your stance determines which foot leads your movement and how your body aligns relative to your direction of travel. Because freeskates are completely unattached, mastering balance and stance orientation is the foundation for all carving and trick progression.
Every rider has a natural default stance, usually determined by which foot feels most stable guiding the lead skate.
It is strongly recommended to practice both your default stance and your Switch stance simultaneously while learning the absolute basics.
Because freeskates rely heavily on fine motor control in independent legs, building asymmetric muscle memory early on makes learning switch significantly harder later.
JMK has published a dedicated video on riding switch here.
For a more detailed look at how pumping with both stances works, check out Pumping.