Add example for each API endpoint

[sabbyanandan]

Note from @BowTiedDeployer:

for every api have a specific example explained

• this is the contract
• this way it is called specifically on it

this gets a better learning curve for using a given api for the first time, after using it once it is enough the theory because you already know an example where you applied it

[LakshmiLavanyaKasturi]

Created a new issue to add examples for the remaining APIs'. Hence marking this issue as done.