Getting A house under contract THEN closing?

[Izaiah Lopez]

So I haven't done anything in wholesaling yet, and here's the reason... There's really 2 questions here. 

When I listen to courses and videos or read articles, they all say "sign the house ASAP then go into closing" and quit frankly it confuses me. 

SO THE QUESTION: When the owners of a house accept your offer and you sign the house under your name to flip it, even tho you signed, are you able to get out of the contract before closing? 

because the house is in your name and your rights to do what you want when you sign for the price agreed, but closing hasn't happened yet, or is closing just the payment... but if that's the case then how do you close without the buyer being there at the same time if he has the money...  I DON'T UNDERSTAND! IF someone could explain I would greatly appreciate it! 

QUESTION #2: Everyone I listen to or talk to say "sign the closing contract then bring in the buyer like an hour later for the assignment agreement"

Because if you sign the closing contract with the seller and the buyer backs out last second, you already signed the closing contract aren't you stuck with the house at that point?  

Thank you for your time!