I am trying to integrate amazon skill kit in my website without an amazon echo unit. I want to implement voice commands on my website using the laptop/PC microphone instead of a
Yes, the Alexa Voice Service does exactly that: Lets you process audio from any source, like a laptop or tablet or phone, using the Alexa Skills Kit. No Echo is necessary.
Make sure you read through Getting Started with the Alexa Voice Service and the Reference Implementation Guide; there are a lot of configuration steps that need to be done to make everything work together.
Did you get the Alexa Voice tutorial you linked to working?