Can somebody please help me understand this level 2 terminology, i simply cant understand what 

"hit the bid" and "hit the ask" means? 

 

I have tried to look it by googleing and have come across a definition from investopedia

Hit the bid= means if one market maker is selling a stocks for 20 $ and another market maker is selling the same stock at 19 $, so the first market maker that is selling for 20$ is now deciding to sell the stock at 19 $ then they are said to "hit the bid". They are in other words deciding to sell the stock at lower price.
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(But what happends to the second market maker that is also selling the stock at 19 $, have they vanished? And is it a good sign or a bad sign when a stock hits the bid? is it bearish or bullish? and why did the market maker lower the price for the stock?)

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Hit the ask= ? i dont understand it

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Also i have watched tim grittanis level 2 videos and if the stock is hitting the bid then it would be red color on the time & sales and if the stock is hitting the ask it would be green color on time & sales. So red is a bearish sign and green is a bullish sign when looking at the printer or time & sales ?

 

And i would really appreciate if somebody could also give me good example on how to "use" 

the info from "hit the bid" and "hit the ask" together with  Time & Sales information when buying stocks and shorting stocks.

 

I am sorry for all this questions, i would be very thankful if somebody could help me out.