First, locate your dominant upper limb.
Most humans possess two upper appendages, commonly referred to as "arms." Identify the one with which you exhibit greater dexterity—this will likely be your dominant limb. If uncertain, perform a simple task such as pretending to throw an imaginary sphere. The arm used is usually the dominant one.

Initiate neuromuscular coordination.
Begin the process by generating an electrical signal within the motor cortex of your brain (specifically the precentral gyrus). This action potential will travel via upper motor neurons through the corticospinal tract, decussating at the medullary pyramids, and synapsing with lower motor neurons in the spinal cord.

Transmit the command to your hand.
The signal will proceed through peripheral nerves (primarily the median, ulnar, and radial nerves) toward the muscular structures in your hand and fingers. Acetylcholine will be released at the neuromuscular junctions, causing depolarization of muscle fibers and subsequent contraction.

Extend your index digit.
Flex and stabilize all other fingers except the "index finger" (digitus secundus). Use extensor and flexor muscles in careful synergy to isolate this finger, allowing it to protrude in a confident, button-approaching posture.

Engage visual targeting systems.
Utilize your ocular apparatus—more specifically, the photoreceptor cells in your retinas—to identify the "button." Light reflected from the button enters your cornea, is focused by your lens, and hits the retina. The resulting image is transmitted via the optic nerve to the occipital lobe for processing.

Adjust for depth perception.
Use binocular disparity between your two eyeballs to judge the button’s distance in 3D space. This allows you to correctly calibrate the trajectory and force needed for successful button engagement.

Initiate the pressing sequence.
Begin forward motion of the extended digit by contracting appropriate forearm and hand muscles. As the fingertip makes contact with the button's surface (often a plastic or metal interface), mechanoreceptors in your skin—like Merkel cells and Meissner's corpuscles—register the tactile feedback.

Apply downward force.
Increase pressure until the button depresses, typically activating a mechanical or electronic switch beneath the surface. This will often produce an audible "click," confirming successful actuation.

Receive neurological reward.
Upon pressing the button, your brain may release small amounts of dopamine as a reward for task completion. This is an optional but highly encouraged part of the process.

In other words...
You just need to touch the start button.
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