Fields Side-by-Side Within Two Columns

[SidSidSid16]

I would like to create a form with two fields side-by-side. I think of implementing this by registering a new field with two options, 'left' and 'right'. In each option, I will list all available fields which the user can then select.

from django import forms
from wagtailstreamforms.fields import BaseField, register
from wagtail.core import blocks

@register('two_columns')
class TwoColumns(BaseField):
    widget = forms.Select
    icon = 'list-ul'
    label = 'Two Columns'

    def get_form_block(self):
        return blocks.StructBlock([
            ('left', ),
            ('right', )
        ], icon=self.icon, label=self.label)

Am I on the right track and how do I continue with this, (how do I list all fields)?