So, if you want to create a leaderboard you have previously had 2 options. Either use the built in one, that has very low customisability (you can't even move it :/) or use dialogs. Well now theres a 3rd way! My scoreboard library. It is highly customisable, and mostly automatically updating. For example you want a DOTA style scoreboard with a hero kills scoreboard: Just add a 'Add leaderboard column (Kills, Hero Kills)' and it will update every time a hero dies. With no extra triggers. You can move it with the 'Move dialog' action, and the header can be changed to whatever you like. There is also a 'custom' column that does not auto-update, but won't take much to make a trigger to do it.
If you want to add a scoreboard to you map, check it out. Very simple to use and very customisable.