Hi all, again!

I was finally able to compile and run a simple app on my 84PCSE.

However, I have a problem. I have not yet found a tutorial that explains how and what to do to accomplish the simple task of displaying a splash screen. Can anyone help me?

That's a fair question. When you say app, do you mean App, or do you mean program? If program, you can use the Doors CSE sprite functions together with a 1-bit, 2-bit, 4-bit, or 8-bit image converted using SourceCoder 3. Working with the LCD is somewhat tricky, although certainly not impossible; there is a good guide to the LCD on WikiTI. For documentation about the Doors CSE sprite/image functions, check out its wiki.

I meant an App. Also, I tried to use a Doors CSE routine, but I don't know how to put it in my App. I tried to use BCALL and it didn't work...

You'd have to have the source code to Doors CSE to use that routine as an application can't (easily) access another application's routines since they both need to occupy the same space ($4000-$7FFF). You might want to check out some sample code, for example matreyfontias posted a routine
here which you can use. It supports sprites up to 256x256 (so you won't be able to fill the whole screen with it). I haven't worked with the CSE so i'm not exactly sure how it works, but contra did a code review of Kerm's bouncing ball demo, which you might be interested in reading. I'd also recommend reading the WikiTI article Kerm posted and asking here if you've got any questions on what you've read.

Drawing a sprite and working with the LCD isn't as simple as you might expect, though once you figure it out i don't think you'll have too much of an issue with it.