i have several questions about tuning a trumpet: 1. so the tuner is supposed to be set to A440 correct? 2. does this mean that i have to play a concert A on the trumpet to tune or can i play any note and tune while it is set to 440? 3.which note should i tune first? 4.approximately how much should the main tuning slide be pulled out???? Im always flat so i know i need to have the slide pushed inwards. Thanks everyone!!!