Define your models

After CRUD creation you must have to modify your foxx/cruds/APP/models/<model_name>.js file

const db = require('@arangodb').db
const joi = require('joi')
require("@arangodb/aql/cache").properties({ mode: "on" })

// Sample to load an external collection as list
// var users = db._query(`
//   FOR doc in users RETURN [doc._key, doc.username]
// `).toArray()

// Tags definition sample
// var tags = db._query(`
//   LET tags = (
//     FOR doc IN posts
//       FILTER doc.tags != NULL
//       RETURN doc.tags
//   )
//   RETURN UNIQUE(FLATTEN(tags))
// `).toArray()

// { r: new_row, c: "classname", n: "name/id", t: "type", j: joi.validation(), l: "Label", d: [["data", "list"]], tr: translatable? true or false },

// { r: true, c: "1-1", n: "title", t: "string", j: joi.string().required(), l: "Title", tr: true },
// { r: true, c: "1-1", n: "color", t: "string:color", j: joi.string().required(), l: "Pick a color"},
// { r: true, c: "1-1", n: "position", t: "integer", j: joi.number().integer(), l: "Position" },
// { r: true, c: "1-1", n: "online", t: "boolean", j: joi.number().integer(), l: "Online?" },
// { r: true, c: "1-1", n: "published_at", t: "date", j: joi.date().format('YYYY-MM-DD').raw().required(), l: "Published_at" },
// { r: true, c: "1-1", n: "time", t: "time", j: joi.string(), l: "Time" },
// { r: true, c: "1-1", n: "desc", t: "text", j: joi.string(), l: "Description" },
// { r: true, c: "1-1", n: "user_key", t: "list", j: joi.string(), l: "User", d: users },
// { r: true, c: "1-1", n: "image", t: "image", j: joi.string(), l: "Pictures" },
// { r: true, c: "1-1", n: "file", t: "file", j: joi.string(), l: "Files" },
// { r: true, c: "1-1", n: "tags", t: "tags", j: joi.array(), l: "Tags", d: tags },
// { r: true, c: "1-1", n: "items", t: "multilist", j: joi.array(), l: "Multi List of tags", d: tags },
// { r: true, c: "1-1", n: "position", t: "map", j: joi.array(), l: "Coordinates" },
// { r: true, c: "1-1", n: "html", t: "code:html", j: joi.any(), l: "Some HTML" },
// { r: true, c: "1-1", n: "scss", t: "code:scss", j: joi.any(), l: "Some SCSS" },
// { r: true, c: "1-1", n: "javascript", t: "code:javascript", j: joi.any(), l: "Some JS" },
// { r: true, c: "1-1", n: "json", t: "code:json", j: joi.any(), l: "Some Json" },

const model = function() {
  return {
    model: [
      // { r: true, c: "1-1", n: "name", t: "string", j: joi.string().required(), l: "Name" },
    ],
    // 1-n relations
    // Don't forget to create your collection in setup.js
    //sub_models: {
    //  authors: {
    //    fields: [
    //      { r: true, c: "1-1", n: "post_id", t: "hidden", j: joi.string().required(), l: "Post ID" },
    //      { r: true, c: "1-1", n: "name", t: "string", j: joi.string().required(), l: "Name" },
    //    ],
    //    singular: "author",
    //    key: "post_id",
    //    columns: ["name"] // Display on listing
    //  },
    //}
  }
}
module.exports = model

Fill return array with you fields definition.

Here a post sample

const db = require('@arangodb').db
const joi = require('joi')
require("@arangodb/aql/cache").properties({ mode: "on" })

const model = function() {
  var tags = db._query(`
    LET tags = ( FOR doc IN posts FILTER doc.tags != NULL RETURN doc.tags)
    RETURN UNIQUE(FLATTEN(tags))
  `).toArray()


  return {
    model: [
      { r: true, c: "1-1", n: "name", t: "string", j: joi.string().required(), l: "Name" },
      { r: true, c: "1-1", n: "tags", t: "tags", j: joi.array(), l: "Tags", d: tags },
      { r: true, c: "1-1", n: "desc", t: "text", j: joi.string(), l: "Description" },
      { r: true, c: "1-1", n: "published_at", t: "date", j: joi.date().format('YYYY-MM-DD').raw().required(), l: "Published_at" },
      { r: true, c: "1-1", n: "image", t: "image", j: joi.string(), l: "Pictures" },
    ]
  }
}
module.exports = model

Here you go ! You should be able now to create your new object ... Assets (pictures or files) will appear only on edit page.