In the top navigation bar, click the mode selector and select Financials mode.
Click Financial settings and select Markups.
To the right, click Edit.
Under "Default value for future channels", set a value to apply to future booking channels that do not have a specific markup.
Under each booking channel, edit the markup and note that for Misterb&b listings, the markup is the percentage set for Guesty reservations, which are Booking Website and manual reservations.
If the resulting price is not a whole number, Guesty will round it up to the nearest whole number. For example, if a 3.5% markup is added to a nightly rate of 51 USD, the resulting price will be 51 x 1.035 = 52.785, and Guesty will round that up to 53 USD.