Two easy way to download video from youtube.
From keepvid
Search video which is you want to download in search bar
Open video then right click and copy video link
You need java if you have no need if you don't have download
java and install it
Paste copy link to download bar and click on download
Now video format shows
Chose format and it will download start...........
From ytd video downloader
Open ytd video downloader.It will auto generate video link which you copy from youtube video link
Select format in download quality then just click download,video download process start.............