Hiya there Spenk!
I'm guessing English isn't your first language from your code, isn't it? xD Ah, well that's okay.
First and easiest solution that comes to mind is using a Pause. When your screen is full, place a Pause there, which will allow the reader to read the first page as long as it lasts there. Then, when enter is pressed, you display the second screen. It's quite easy, but the disadvantage is that you can't quite "scroll", between the two pages.
Second would be Pause again, who would've thought? xD If you store a long string in a variable, let's say, Str1, you can display it through Pause and be able to scroll horizontally, left and right, to view the entire string. But somehow, I don't think that's what you want. ;P I'm guessing you'll want to scroll up and down pages, right? Well, then there's my third answer, which is easily the most complicated, so pay close attention.
First things first, you will need all of the text we will display. Just write it down for now, we'll format it later. For my example, I wrote up a partial quote from HTTYD. :D
Astrid: Why didn't you?
Hiccup: I don't know... I couldn't.
Astrid: That's not an answer.
Hiccup: Why is this so important to you all of a sudden?
Second, a getKey loop. Ask the user to input a key, probably up and down, and enter to exit the loop.
getKey → K
The last bit of code says that the user does not enter a key, repeat the loop again. It helps with code by not running code if a key isn't pressed, especially when you have a lot of code after the getkey. Now, the tricky part, the scrolling. For that, we'll borrow a line from the "Movement in Maps" page in the wiki here. The one we will need is…
In-short, without explaining all of the technicals, is that if Up is pressed, the line adds 1 to A. If Down is pressed, A is subtracted by one. The min( and max( commands keep A confined in the screen to avoid errors, but we're going to need to change that later. For now though, we'll just plop that right into the program for now.
getKey → K
Next, we'll need a way to display all of that text. Lucky for you, this is all on the homescreen, so you have Output('s wonderful word wrapping on your side. If you didn't know, if your string or text you outputted is too long for the screen, aka longer than 16 characters, it drops the text down to the next line. If a sentence you have on a line has 12 characters, for example, you will then follow it with 4 spaces to put the next sentence on the next line.
Here's my example formatted with the spaces. Notepad++ is real helpful in doing this task, as it tells you how many characters are in each line you write, which is why I do all my computer/optimization programming on it.
Hiccup: I don't
not an answer.
Hiccup: Why is
this so importa-
nt to you all of
You may miss one or two spaces, so be prepared to go back to your string to adjust it to fit the lines.
The final command we will be using is sub(, short for substring. Basically, it can break down your string into small portions, or snippets, if you only want to display a part of your string. The parameters are [String],[Starting Point],[Length]. Now, remember your uber-long key line from before? If you push up, 1 is added to A, and if you push down, 1 is subtracted from A? Here's how it'll work here.
The homescreen's dimensions are 16 characters long and 8 characters/lines tall. 16x8 = 128. So, for your first screen, you will be displaying from your string 1 character to 128. It's a ridiculous number, I know, but it'll make things easy in the end. Now, if you push down, you'll want to display the next line, which starts at character 9 and ends at character 136, which is still 128 length. So, here's how sub will play in.
This does exactly what I described we needed above. When A=0, characters 1 to 128 will be displayed, as 8x0 = 0. When A=1, 8x1 = 8, and 8+1=9, and so on. However, now we're going to need to change those min/max values for the long movement line, with the min being 0, and max being however many extra lines your text is. My text has 14 lines, minus the 8 of the homescreen leaves me with 6 extra lines. So, it would look like this.
getKey → K
And there you go. This works well for displaying something like a long text message, but if user input's needed, like I'm afraid that it is for your program, then it may not work out well, and I might have to go back to the drawing board for some new code.
The 4th method would be to use the Text screen instead of the homescreen, as you can fit more text there.