Well, there is no best process. You talk about music creation or re-creation of existing music from scratch.
You have options:
- Playing on MIDI controllers
- Writing notes/events manually in Logic Score or Pianoroll
- Writing notes with the step-function
- Importing MIDI data
- Playing electric instruments with pickups to preamps
- Recording acoustic instruments with microphones
In most cases, playing the music is the best way, at least for the music. But you must be able to play and simulate several instruments on the right controller for each instrument. For example, playing blown instruments on a keyboard is possible but you need to be a sensitive player and know the original instrument well. Many players prefer a breath controller for these instruments, either a breath controller box and a keyboard or – better – a dedicated windcontroller, which is an electronic instrument that produces MIDI data.
Drums can be played on a keyboard, but you may prefer electronic drums to trigger virtual instruments of your choice. A keyboarder may be able to simulate guitar techniques, but a guitarist may prefer to play on audio tracks or/and use a MIDI-guitar for scoring. String and brass sections are often played on MIDI keyboards, but this gets difficult for solo instruments. The possibilities are endless and depend on your personal skills and your equipment.
Writing the score manually for virtual instruments is often done and people are quite successful if they have the feeling and experience for their instruments and music. You may need a lot of corrections and fine-tuning to produce convincing tracks this way because written notes in a DAW are normally quantized, they give a machine-like feeling. On the other hand, if you make machine-like music, this may be your way.
You can also write your notes while you compose and play them afterwards on a controller for better feeling and expression. Writing notes, bringing them to the right timing and finally adding expression, pitchbend etc. with a controller is also a widely used method. Most musicians who write for several instruments use a mix of several techniques.
There is not much to say about imported MIDI data. The quality depends on the person who made the score. Can be good or not, can be right what you need or just a layout which you refine or use as a template for your own playing or writing.
Depending on your instrumental skills you rather may prefer to record on audio tracks than using MIDI. But be aware that apart from instruments with electric pickups you need the right microphone and a good room for good recordings. Such a setup can get quite complex and expensive.
If you have no instrumental skills at all, try writing the score manually but also learn basic playing on your keyboard, this will help a lot in the future. If you can play one or more instruments, think about recording them on audio tracks or try to simulate them with appropriate playing on your MIDI controller.
I hope, this short overview could provide some starting points for you.
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BTW, in your setup I miss an audio interface but you have an USB microphone. You seem to believe, that using your computer alone is enough. In the long term this is not the case. The built-in audio interface of your Mac is not good enough to hear a mix as good as possible. And you have no possibility to use the right microphones and preamps for different instruments. Of course you can start making music with your current equipment. Just expect that some extensions of your setup may be necessary in future. Not to forget good studio speakers and an acoustically treated room for listening and probably for recording.