How to create a midi controller (novice)

I’ve seen a recorder used as a midi controller and I’d like to do something similar.

I want to set up 16 buttons that when pushed (in specific combinations) send a signal via bluetooth to a device like an arduino or raspberry pi. This divide would be programmed to identify the button combination selected and which  midi note it corresponds to. When the signal is received the device needs to be programmed for volume and on/duration/off too. One pressure sensor will determine the midi sound on/off (duration) and another would determine the volume. These instructions will be sent to an audio output device to be heard.

What I have:

I have a list of key combinations to midi pitches set out in a matrix. I’m confident that if I found a pre-existing programme that does something similar - I could edit it for my own purpose.

What I need:

I’m a complete electronics novice and need pointing in the right direction:

What electronics do I need to purchase in order to mock up this circuit?

Is there a basic programme (e.g. python) I could edit to do the following:

1. When buttons x,y&z are pushed + (octave) sensor position 1 (3 octaves to choose from) selected = play  midi note x

1. sensor=volume (graduation/sliding scale from v.quiet to v. loud)
2. sensor=sound on/sustain/off)

thanks