What is the method that is used to calculate the price of a new Token on the Exchange in relationship with the total number of issued Tokens?

We know that most exchanges use the formula marketcap = price * circulating supply

For ex.: If I issue 100 new tokens, are these 100 tokens considered as being already in the circulating supply?

And how to calculate the increase/decrease of price on the exchange?

For ex.: if price of token is 1 USD and someone buys 10 tokens, based on a total supply of 100 tokens, what would the new price be?