A few questions.

[Jay the Editor]

[1]: How do the triggers should like if I want the player to double click the hero to choose that particular hero? As I want the first click to view the hero stats and abilities.

[2]: What is the difference between "An exact match" and "A substring"? These both particular are at "Event ---> Player - Chat Message"

[3]: How can I make an enemy to automatically use their abilities such as Blizzard or any other active spells but not Auto-activable spells like Bloodlust, etc. (Simple AI)

[4]: How can I 'notify' (just like when complete building a structure. there's a green notification) at the mini map when I create a unit at there?

 

[Dr Super Good]

[1]: How do the triggers should like if I want the player to double click the hero to choose that particular hero? As I want the first click to view the hero stats and abilities.

There is an event that detects unit selection. First selection takes you to a dummy showing stats, second selection chooses the hero. You could also use trackables if you do not mind them remaining on the map.

[2]: What is the difference between "An exact match" and "A substring"? These both particular are at "Event ---> Player - Chat Message"

Exact match means the entered chat message has to be exactly the string that you specified for the event to fire. In substring mode the event will fire when any chat message contains the string you specified (is a substring of the message). Both are case insensitive so the chat message "GO" will fire an event looking for "go".

Examples...
fires trigger / does nothing

Message with "GUI" as exact match.
player: gui
player: gui compiles to jass
player: g u i

Message with "GUI" as a substring.
player: gui
player: gui compiles to jass
player: g u i

[3]: How can I make an enemy to automatically use their abilities such as Blizzard or any other active spells but not Auto-activable spells like Bloodlust, etc. (Simple AI)

An AI player will automatically do this for most abilities without you needing to change a thing. Some abilities such as those from items changed to be for units lack AI to cast. Additionally some complicated abilities such as Death Pact will not be cast by the default AI. In both those cases you will have to script them to be cast (trigger enhanced AI for them).

[4]: How can I 'notify' (just like when complete building a structure. there's a green notification) at the mini map when I create a unit at there?

You can create flairs with a custom visual via JASS script. No idea if you can create custom flairs using GUI but I know you can do some standard flairs.

 

[Maker]

1)
Player selects a unit
if hero[pnumber of trig plr] = trig unit then
--hero selected
else
-set hero[pnumber of trig plr] = trig unit
endif

4) Cinematic - Ping minimap

 

[Jay the Editor]

Thanks for all the information for you both gave, Maker and Dr Super Good. =) It's really helpful.