Pre-check multiple checkboxes in Rails ActiveAdmin

I need to pre-check multiple checkboxes in form for habtm model in ActiveAdmin while creating new object. Array with ids of nested model taken from array in third-party model database record. My current configuration:

ActiveAdmin.register Hotel do
  permit_params page_ids:[]
  ...
  form do |f|
    ...
    f.inputs 'Pages' do
      f.input :pages, as: :check_boxes, collection: Page.order('position asc')
    end
    f.actions
  end
end

class Hotel < ApplicationRecord
  has_and_belongs_to_many :pages
  accepts_nested_attributes_for :pages
  ...
end

class Page < ApplicationRecord
  has_and_belongs_to_many :hotels
  ...
end

Array with ids of pages that should be prechecked:

Setting.find_by_name("defined_pages_ids").value.split(',').map(&:to_i) # [1,2,3,4]

What solution do i need to implement pre-checking?

You need to override creating a new instance of Hotel model, and prepopulate needed data

  controller do

    def new
      @hotel = Hotel.new
      @hotel.pages << Page.all
    end

end