i am creating First campaign with adwords, i want to display ads on youtube, i have done rest of settings,friends just suggest me what keywords must i use for it. "i want to place ads only on youtube".
your keywords will need to be relevant to your website. Try using the keyword suggestion tool that adwords provides.
You have to set your content network in adowrds to target youtube specifically. But not sure if you can traget keywords in that case.