Question: Sample config file for Radicale

I checked: vdirsyncer/config.example at master · pimutils/vdirsyncer, but I am still confused about customizing it for my Radicale server, which has files as follows

$ cd ~/Radicale/collections/collection-root
$ tree

└── anish
    ├── 6229e809-b885-b85b-d83a-a799bfa7040e
    │   ├── 00120af9-a3d0-4044-90ef-1d5fa2366284.ics
    │   ├── 00b3014e-4a23-42bd-a3a7-ee759d5522bb.ics
    │   └── ffc953b7-09f6-4725-9c44-1969fde1a25a.ics
    ├── d994d01f-7150-c6d0-6d3d-b6c4d9ff8b30
    ├── e5b93e12-3aa4-b252-4bfe-ad683ec3bbd3
    ├── e8747b12-ac9d-d3f1-9ba6-2c71b8c2dd08
    └── f69ef521-c33a-43bd-eb2c-86e14d0fa447

So, I have 5 calendars, out of which 4 of them are empty and one of them has 3 events. Each one of these calendar has file .Radicale.props that describes the metadata of the calendar:

$ cat  6229e809-b885-b85b-d83a-a799bfa7040e/.Radicale.props | jq
{
  "C:supported-calendar-component-set": "VEVENT",
  "D:displayname": "Q1 People",
  "ICAL:calendar-color": "#ffababff",
  "tag": "VCALENDAR"
}

How to include all the calendars into vdirsync, so that I( can access it with khal?

Start by reading the linked config.example and comparing its calendar configuration with the Radicale collection tree and .Radicale.props metadata shown here. The documentation should explain how to include all five calendars and make them available through khal, with an example matching this layout.