I'm making a DNN Module and I want to add functionality similar to HTML Module. So I'm adding a telerik radeditor to the Edit.ascx along with dnn:Label. I also want to a button labeled Save that is of the same style in settings.
I'm wondering how I add a button like that and also how should I be saving the content that's entered into the radeditor? Does it save similar to settings or am I going to have to save the data in whatever database I have available?
You just add a button the same way as you would with any other .ascx control - by adding an control onto the page. You would then normally hook up the button click event to your save routine.
You should save the results into your own table, based on either the moduleId or the TabModuleId, depending on what the module is for. You will need to create your own table, because you'll need to save the resulting html into an nText field in Sql Server, so that you have enough space to store the results.
There are plenty of open-source text/edit html modules around. I would inspect the source code of one or more of these to get ideas.