Hang on, I found an answer. I looked in AUM wdl resources and found the code below. I should be able to change it for my purpose:

/// a touch and show panel wdl by Dreamkiller and Realspawn

///////////////Bmaps/////////////////
bmap test_for_5sec = <test.bmp>; (or your own file name)
//////////////Panels////////////////////

Panel test_panel
{
Layer 2;
bmap = test_for_5sec;
flags = refresh,d3d,transparent;
}

string textap_str = "You did it !";

text you_did
{
pos_x = 300;
pos_y = 240;
font = standard_font;
string = textap_str;
layer = 10;
flags = transparent, d3d, center_x, center_y, narrow;
}

///////////////////new/////////////
function text()
{
set you_did.visible,on;
set you_did.visible,on;
waitt(80);
set test_panel.visible,off;
set you_did.visible,off;
wait(1);
} }

ACTION Show_pictext {
SET MY.ENABLE_IMPACT, ON;
SET MY.EVENT text;
}