How to Warm Up on Trumpet 

Thanks! Happy to hear it!

Thank you, it means a lot! Happy to help!

When I'm in a crunch, I do the chromatic scale from Ab down to D and back up quietly for as long as I have. This serves a similar function to the long tones, but you can also work out your finger muscles, and your articulation if you choose to articulate it. You could also play the chromatic scale up an octave from low C to middle C, or play through any major scales in the low and middle registers at a relatively quiet volume. The goal is just to try not to bludgeon your face right off the bat. Good luck!

As long as all notes are proportionally off and you are playing alone.. It doesn't really matter. It can't hurt to use a tuner tho.

There are two separate issues here: One is knowing what notes you're playing at any given time, which can be tricky when starting out because so many notes on the trumpet use the same fingerings. It doesn't hurt to use a tuner, but your best bet is to anchor yourself on low C (a helpful anchor as the lowest open note on the trumpet) and feel what it feels like to move to a middle G and middle C. Over time those notes will feel and sound significantly different. The second issue is playing in tune. In a vacuum, as long as you're in tune with yourself, it doesn't make a huge difference unless the way you're playing the trumpet is causing you to play very sharp or very flat. (As a general rule, your tuning slide should be out around an inch, but it can vary from player to player and in different environments.) However, it is important to tune the trumpet if you're playing with an ensemble to ensure that everyone's on the same pitch. Many factors, including most notably the temperature of the room, can affect the intonation of the horn, so it's worth checking your intonation before you play with other musicians.