Experience has taught us that newcomers to jazz guitar don't have the skill or the confidence to just come along to a club meeting and jam with others. So, rather than have them sit on the sidelines watching, the first hour 7.0pm to 8.0pm of each club meeting is dedicated to beginners. It is a more structured session in that everyone knows in advance which numbers are going to be played and can develop at their own pace, with the support of one or more experienced players.
At the March 2019 meetting, the beginners session was led by Nick Harris and Jon Wilks. The beginners started of playing in pairs, taking it in turn to comp, play the melody and or improvise. Nick commented on how many of the improvisations were based around the melody, which is fine, but the next step would be to use the harmony. When asked he gave us an example of basing the improv on Arpeggios and Triads and went on to say he uses mostly uses Triads and Arpeggios in his improvisations. He stressed the importance in learning the triads and Arpeggios for any song you want to improvise on.
There are of course a number of good learning tools to help us to learn Arpeggios;
Mini Fox has a Book and Cd set entitled "Arpeggio Studies On Jazz Standards"
Matt Warnock has a download ebook on his web site "Arpeggios - The Complete Guide"
I have just downloded an App based book from The iStore for my iPad by Joseph Alexander called "Chord Tone Soloing for Jazz Guitar" sub titled "Master Arpeggio-Based Soloing for Jazz Guitar".
So lets start studying and see where we get to.