The answer is up to you as far as when you'd gather the equipment you'd like to use, start with a channel idea then record the videos. My advice for equipment is to start with what you have which is a smartphone, come up with an idea and topic you are passionate about, learn how to edit the videos in iMovie and record!
This professional recommends the following next steps:
- Determine what you'd like to talk about on your YouTube channel
- Gather the necessary filming equipment
- Film 1 video to see if you like it
- Edit and upload the video