Using EQ

When I try to adjust audio using he equalizer you get a 5 sec. preview. How can I get the music to play for as long as I want to work on it. 5 sec. does not cut it.

“Some” Audacity effects, but NOT including the Equalization effect, support “real-time preview”. An example being the “Bass and Treble” effect. With these effects, you can preview the entire project if you wish. You can also adjust the settings during the preview and hear the setting in real-time (hear the affect of the changes as you make the adjustments). This is very convenient for many types of effect.

“Real-time preview” effects are a recent addition to Audacity, and over the next few releases you can expect to see more real-time preview effects

For other effects, preview is a fixed period with a default of 6 seconds. The effect parameters cannot be adjusted during preview playback.
The length of the preview can be set in Audacity’s “Preferences”:
Edit menu > Preferences > Playback

There are equalizer plugins which work in Audacity which work in real-time, e.g. …