First things first
Tune it.
Every single time you pick it up. Thirty seconds now saves the whole hour.
Tuner
One string
at a time.
Uses the microphone in this browser only. Nothing is recorded and nothing leaves the page. Pluck one string, let it ring, and watch the needle.
The six strings, thickest to thinnest, are E A D G B e. "Eddie Ate Dynamite, Good Bye Eddie." The matching button lights up when the tuner hears one of them.
Flat means the note is too low: turn the tuning peg so the string gets tighter. Sharp means too high: loosen it. Small turns. A quarter turn is a lot.
Always tune up to the note, not down to it. If you overshoot and go sharp, loosen until you are a little flat, then tighten back up. Approaching from below takes the slack out of the tuning gear and the note holds.
If it will not settle, the room may be too loud, or the strings may be dead. Grey, gritty strings do not stay in tune no matter what you do. The club can help you restring at a meeting.
No microphone permission? Your browser asked and you said no, or the campus network blocks it. Any free tuner app does the same job.