@PeteS This is a VERY common issue when joining audio clips
It is best practice to ALWAYS add a slight fade out to the previous clip and a slight fade in to the audio clip you are placing behind it (the fade only need to be VERY slight that you won’t notice one fading out and the other fading in - just enough to “smooth” the join
Some DAWs will do this automatically
The “click” occurs because there is a “jolt” in the waveform
If you imagine the waveform going up and down a centre line, some of the waveform is “above” and then it snakes “below” this centre line
If you join 2 pieces of audio you could be joining a point where the waveform if below the centre line directly with another clip that has been cut whilst in the upper half - you will then lose the smooth line of the natural waveform, which results in the click
This would be soo much easier to show with diagrams but hopefully you get the point
The point where the waveform crosses the centre line is known as the “zero crossing” - you can set some DAWs to always cut at this point to minimise the risk of this “clicking” in an attempt to keep a smooth waveform - however this can still be a bit “hit and miss” so the age old fading out then fading in of clips is the way to go
If you overlap the clips slightly some DAWs will automatically put in a “cross fade”, which is the same as fading method but the clips overlap, which often gives smoother results