I would like to buy a second-level domain name (e.g. example.com) and I will
run web server on my own machine (named www, having public IP address).

Is this sufficient for my machine to be accessible by visitors via browser
with http://www.example.com?

I expect that every visitor machine accessing http://www.example.com will first ask
it's DNS server if it knows the IP address of www.example.com.
If it doesn't know. The DNS server will ask the root server on the address of .com
top-level domain. Then it will ask .com top-level domain if it knows the IP address
of www.example.com and it should be there because I bought it. So finally it will send the IP address to the visitor's DNS server and then visitor's DNS server will send the IP
address to visitor's machine?

I would like to avoid installing and configuring own DNS server (I have only one laptop). Is my expectation correct that I don't need to install own DNS server?

If yes/no, please describe a little the reasoning behind the scene.


Question: In TOS, how many shuttlecraft were aboard the U.S.S. Enterprise NCC-1701?
Answer: In the TOS episode "Omega Glory", it is stated the Exeter starship (like the E) has four shuttlecrafts aboard.  I would presume the E 1701 would also carry four.