How can I control the yaw, pitch and roll of a flying object?

Hi, I want to make an object fly through space and control its yaw, pitch and roll through buttons on the screen and with accelerometer input. At first I thought euler angles will do the trick as they describe precisely the yaw, pitch and roll of an object but I was wrong. I am guessing this can be achieved through quaternions but I don't know anything about them. Please help me figure out what changes I need to make to the code below in order to achieve my aim. In the code below, the y-axis represents yaw, the z-axis roll, and the x-axis pitch. Thanks.

     void LateUpdate () {
         if (btnsAction.leftPressed && !btnsAction.rightPressed) {
             eulerY -= 10f*Time.deltaTime;
         }
         if (!btnsAction.leftPressed && btnsAction.rightPressed) {
             eulerY += 10f*Time.deltaTime;
         }
         if (btnsAction.upPressed && !btnsAction.downPressed) {
             eulerX -= 10f*Time.deltaTime;
         }
         if (!btnsAction.upPressed && btnsAction.downPressed) {
             eulerX += 10f*Time.deltaTime;
         }
         eulerZ -= 10f*Input.acceleration.x*Time.deltaTime;
         rotation = Quaternion.identity;
 
         rotation.eulerAngles = new Vector3(eulerX, eulerY, eulerZ);
         transform.rotation = rotation;
 
 
     }