a lot of people will not like this suggestion, but try creating an object that resembles the indent you want to put in your mesh, and then perform a boolean subtract. i'm assuming that you want to create one of these indents for each button, so the best suggestion (to avoid a boolean error and having both objects just disappear) is to create all the 'indent objects' and then combine them all so they're technically one poly object. then have that new object intersect with the mes you want to indent from, and perform your boolean subtract.