Bard spell casting question

[Dugahst]

The rulebook states the following;
Because you’re a bard, you can usually play an instrument as part of your Material Casting and Somatic Casting actions, so you usually don’t need spell components or another hand free. You can usually also play an instrument for your Verbal Casting actions rather than speaking.

So if I'm playing an instrument to cast a spell, and the spell has 2 or all 3 of those actions-- does that mean that they are condensed into 1 action (playing the instrument)?

So in effect a spell such as summon monster would only cost 1 action instead of 3?

[Thebazilly]

Casting the spell would still be 3 actions, they would all just be Somatic or Verbal casting actions. That way the Bard doesn't need a spell component pouch or a focus.

[Ironwedge]

Multiple actions combined together are referred to as "activities" The action cost is the same, being 2 or 3 actions, but it is considered one activity. Basically, you say "I do this thing..." and you use up the actions it needs to be done.