Group Checkbox Insert

I have a group checkbox input that is failing to insert into the database. I have followed the instructions for Wappler version 3 tutorial. However, though the record is added to the database, it does not add all the items checked in the group. It only adds the last checked item. It seems that I’ve missed something that should gather the array. Should I put brackets on the name=“school_type” of each checkbox?

Any suggestions where I can look?

Below is the group checkbox code :

<div class="form-group col-md-6 col-lg-4 col-xl-4" is="dmx-checkbox-group" id="school_type_group" dmx-bind:value="school_type_group.value[0].$value.split(',')">

<legend class="pb-2" style="font-size: 16px;">School Type</legend>

<!-- group checkboxes -->

<input id="checkbox1" type="checkbox" name="school_type" value="Boarding Day">
<label class="form-check-label ml-1 mr-5" for="input3">Boarding</label>

<input id="checkbox3" type="checkbox" name="school_type" value="Day">
<label class="form-check-label ml-1 mr-5" for="input3">Day</label>

<input id="checkbox4" type="checkbox" name="school_type" value="Night">
<label class="form-check-label ml-1" for="input3">Night</label>

<!-- group checkboxes -->

</div>