I reached Chapter 1 of this game and I knew there were SOME quests which I skipped. Could anybody show me how to view the unfinished quests so that I could complete them. Thanks all.

1. You view all your quests in your Journal ("J" button). There you will find your quests marked as done or unmarked - meaning still open. On the right you have the quest's description, and above the description you will find a tip telling you what to do next to advance with the quest.

2. If you are in Chapter 1 and skipped any quests in the Prologue - you won't be able to go back and complete them. The same applies to other quests - you have to complete them before you continue with the main plot and leave the chapter.

Yes, the journal should be able to tell you everything you need to know; otherwise, you always have the wiki.