Assuming you have downloaded the program, here is the exact procedure.
Before you rush to download that "free" utility from a random forum, you need to know the risks.
Unlike the standard Epson printer driver, which is designed for everyday printing tasks, the Adjustment Program is a service tool. It allows direct communication with the printer’s firmware to modify internal settings, reset counters, and test hardware components.
A safer (though paid) alternative is the WIC Reset Utility (from 2manuals.com). It supports the L3156, has a clean interface, and does not require service mode. Cost is about $10–15 for a reset key. It also allows resetting waste ink counters remotely without risking malware.
A: Technically unlimited, but after 2–3 resets, the physical pad will overflow. Expect ink leaks inside the printer case after the 3rd reset.