The CRUD generator of Gii has done a wonderful job for you, and you already have a list of items in the "index" page and a detailed view of a specified item in the "view" page.
Yii Framework Wiki
Wiki articles in category How-tos tagged with "AJAX"
Showing 1-3 of 3 items.
Render Form in popup via AJAX (Create and Update) with ajax validation & Also load any page via ajax Yii 2.0 (2.3)
There are a few issues with the other solutions I originally used that I found from other wikis. I address the issues I had in this much simpler and shorter way. I am also going to explain what is going into way more detail than others to help people understand what's going on.
How to add a DropDown Language Picker (i18n) to the Menu
Yii comes with internationalisation (i18n) "out of the box". There are instructions in the manual as to how to configure Yii to use i18n, but little information all in one place on how to fully integrate it into the bootstrap menu. This document attempts to remedy that.