JaimeLM wrote: ↑Wed Mar 08, 2017 3:07 pm
* I need to upgrade OC - what issues/coding script errors will this cause?
That depends on your current OC version. But in short, OC upgrade code is pretty bad comparing to other frameworks. You'll have to do a lot of things manually.
JaimeLM wrote: ↑Wed Mar 08, 2017 3:07 pm
* I need to customize a template - what is the easiest way to do so?
You always start customizing template with its settings, then CSS. It is wise to avoid changing template's code as much as possible - very upgrade unfriendly.
JaimeLM wrote: ↑Wed Mar 08, 2017 3:07 pm
* I have a PHP diploma - what is this module thing and where is the best place to learn?
In most frameworks modules is the same thing: some kind of section to display info. For example, tag cloud. RJ already gave you a link to module development page - it'll give you more info.