To create a quest you must first, set it up in the script editor(F11) in this format:
when 1 # Quest Name
name = 'Quest Name'
description = 'Quest description comes here.'
objectives = 'First Objective'
objectives = 'Second Objective'
objectives = 'Third Objective'
# If you want anymore objectives just add another one under the last one with the name 'objectives = 'Fourth Objective''
prime = [0,1,2] # Not sure what this is actually for, would have to ask modern algebra or someone more familiar. But I believe you are meant to put the ids of the objectives.
icon_index = 0 # This is the icon that holds the '0' position (the first one(the top left one)) on your icon set.
then to reveal an objective which effectvely starts the quest just call a script with this line in it:
[quest_id] - Here you will put the quest that holds that number so for my example of how to setup a quest it will be  since it is 'when 1
(objective_id) - Here you will put the objective's ID so for example the first objective in the example quest it would be (0) meaning ' objectives = 'First Objective''
then once the player has completed this objective you should put:
The '[quest_id]' and '(objective_id)' mean the same thing as the previous script call.
You should probably then reveal your next objective; $game_party.quests.reveal_objective (1)
This would reveal the next objective, once this objective has been completed reveal the next one.
Once all objectives have been completed do your reward event and at the end you should call this script:
$game_party.quests[quest_id].reward_given = true
Also if you would like to call the quest journal straight from the map call this script:
$scene = Scene_Quest.new
This about covers the basics.
If you would like to know more just ask.
Also this topic should have been placed under the script support section.RGSS2 Script Support
If you look in the script or on the actual page on here its contains all the information you need!
I use it and have to say have made a great choice!
You should really post something more helpful next time.
Apparently I am back.