Thanks for sharing that link @Edward_Robinson!
We have a website specifically dedicated to DHIS2 application development at developers.dhis2.org, there you can find links to documentation and guides, updates posted by the core team, as well as information about past and future developer events (including the academy Edward shared which took place last month)
In particular, links to course material and recordings from all past trainings can be found here. I’ve linked several of the relevant video recordings below:
- Introduction to Web App Development Webinar
- Platform Tools Webinar
- Academy - Workshop 1 (2 days)
- Academy - Workshop 2 (4 days)
The Platform Tools Webinar in particular should be a good introduction which shows how to use the App Platform to create a very basic app which, as you mentioned @MSP, shows the name of the logged in user.
Here you can also find a list of resources for learning basic web application development, HTML, CSS, Javascript, and React (not specific to DHIS2) if that’s something you’re interested in.