Hi  @adegbengaagoro

So a couple of these ad types are reserved for premium ad partners (I believe spending more that $25,000/month) – namely the Video Comment Ads, Video Poll ads and Video Like Ads.  But there is a way around this.  You can create a Sponsored Story with the post being the link to the YouTube video you want to advertise and the ad will play the video in the ad itself.  You can read how to do this in Scenario 1 of this post:  http://www.mediastreet.ie/blog/2012/02/22/7-unbelievably-cool-facebook-ad-tactics/

Then the Like Ads – it depends, you can advertise your Page and just tell people to click the Like with a traditional ad or you could run a sponsored story ad.  

Event ads can be created when you have a current event to advertise.  Just use the dropdown menu to select the event to advertise.  

Standard ads can advertise an external URL or a Facebook Page.  Hope that helps and this section on Facebook also helps clarify:  http://www.facebook.com/business/ads/