You watch your idea, germinate, and become a reality.
You open your business and then wait for customers to arrive. In a bricks and mortar business - you literally watch for a customer.
Online businesses differ. You actually have to do something to get noticed. Cars driving by traffic that a bricks and mortar business receives would probably be considered "organic traffic". So what can you do if you don't get that kind of traffic?
You might want to consider advertising via Amazon Product Ads. I know what you are thinking.
You are thinking why would I want to advertise my website in a marketplace that where someone is shopping?
Well just imagine if you were in an auto parts store and you were looking to buy a new stereo for your car. You are looking at the different brands, and there you see an advertisement for a competitors stereo at a lower price.
Wouldn't you be interested, in fact you might leave the store and head over and check out the lower competitors price.
My advice is to check it out. Because today, someone is already doing that exact same thing effectively against other products.