In the case of wind instruments, there is no point in tuning until the student's breath and embouchure are stable enough to produce a consistent sound. So, first take the time to practice the basics of creating a resonant sound.
  Sometimes, I hear students tuning with a very breathy, whooshing (or maybe a buzzing?) sound. Whether it's woodwind or brass, such students' tone must first be improved before they can be used in an ensemble.
  Even with that sound, the tuner seems to react and tell you if it's high or low, but I think it's a complete waste of time.
  Once the student has gained some ability to play the instrument and the instrument is in good condition, all instruments should be in tune (depending on the range) to a degree that is not too noticeable.
  In other words, if a group of students can produce a resonant sound, the sound will be in tune without spending time on tuning, but if a group of students is not yet able to make their instruments sound good, no matter how much time they spend on tuning, the sound will not be in tune.
  To put it in extreme terms, whether or not you tune the pitch before practice, it will only match up to the level of each member's consciousness and ears, and it will not match any further than that, so spending too much time on tuning is a waste of time.
  Even if the student cannot adjust right away, listening to them and realizing that they are not aligned and that they are concerned about the misalignment is an important first step.
  First, have two students play the same note and judge whether the two notes are in tune or not, or listen to the "humming sound" that occurs when the notes are not in tune and teach them what it means when they are not in tune.
  Even if students can't immediately tune the pitch, listening to it with their ears and realizing that it's not right and that it bothers them is an important first step.
  I once had two students sitting next to each other play notes that were a semitone apart, and asked them, "Can you tell that the notes are different?" and they didn't know anything at all. I think there are many students who do not understand the meaning of the words "in tune" and "not in tune".
  It's not just students. I heard a long time ago that at a school where someone went to teach, students playing trumpets (The sound is one tone lower than the score) and recorders (The sound is　the same note as the score) were playing together, looking at the same part. The song was the school song. And for years, two melodies with two different pitches were playing at the same time, and no one noticed(or cared).
  In high-level groups, when playing a harmony, even if the notes are not correct at the moment they are played, the members will listen to each other and the balance and pitch will improve the next moment. On the other hand, in groups where each member does not care about pitch or balance at all, they will continue to play even if they play the wrong note.
  When we think of tuning, we tend to think that you just need to pull out the tube (tuning slide) a little when you want a note lower and insert the tuning slide when you want a note higher, but that doesn't solve everything.
  With any wind instrument, there are times when the pitch is so high that the tuning slide is pulled out to the very limit, or when the tuning slide is fully inserted, the pitch may not be high enough.　In these cases, you should assume that there is a problem with the embouchure, breath, or instrument.
  Although this is seen in many schools, do not adjust the pitch while looking at the tuner. There is no point in getting the needle right temporarily if you cannot judge the sound with your own ears, and if you focus only on getting the needle in the center without paying attention to the tone, you may end up worsening your embouchur.
  First, calmly assess why the pitch is not in tune and what stage the students in your band are at.
  Let's consider the causes of pitch not being right for each instrument.