Planning a brass quintet concert is a daunting task. While the formula about to be described is not the only way to plan a concert, it offers a framework that may help you.
First, some numbers.
A full length concert takes between 60-90 minutes of elapsed time. A half takes between 25 and 40 minutes of elapsed time. Plan to take at least 30 seconds between pieces, and fill that music-free space with non-musical entertainment. The easiest way to fill that 30 second interval is to engage the audience with a short monologue. The monologue could be a description of the next piece, an introduction of the musicians, or, if you're particularly talented, a humorous and relevant story.
A typical brass quintet concert piece (or movement) is 2-4 minutes. For a 30 minute half filled with pieces that are on average 2:15 in length, take 30 minutes, divide by 2:45 (2:15 for music and 0:30 for chatter between pieces), and plan to play 10-11 pieces.
A full length concert has an intermission. For practical purposes, you may treat the first and second halves of the concert almost independently, except for a small handful of details:
More serious music should go in the first half of the concert.
If you're playing in a venue where it is expected that you will lead with "The Star Spangled Banner", that effectively precedes the first half.
One way to program a concert half is to:
Start with an upbeat piece such as a circus march.
End with an upbeat piece such as a circus march.
Fill in with pieces in such a way that each piece significantly contrasts with the pieces before and after it.
Circus marches signal an audience to sit down because the serious music is about to start, or they signal an audience that an intermission or the end of the concert is near. Toot Suite Brass Publishing offers a handful of excellent circus marches, and there are many other available brass quintet arrangements of circus marches by Sousa, Karl King, Henry Fillmore, and other band leaders from the late 19th century or early 20th century.
Concerts can be loosely organized around a theme. The theme doesn't have to be adhered to absolutely, and the link between the theme and the pieces may be very tenuous. If you build a program around a "trains" theme and include the Tin Pan Alley classic "Waiting for the Robert E. Lee", the connection to the theme is that both 19th century trains and steamships (like the Robert E. Lee) were powered by steam.