I am trying to watch the series but can’t find the episode when Anakin meets Ashoka. I can find bits of it but not the full episode .
That happened in the very first episode, which also happens to be known as The Clone Wars movie.* Here it is on IMDb - http://www.imdb.com/title/tt1185834/
*(And by "very first", I mean the one that comes first according to airdate. But The Clone Wars had a really crazy airing schedule compared to the chronological order of the episodes, so in the movie actually takes place several episodes in if you're following the correct timeline as given by StarWars.com.)
They meet during the events of the Star Wars: The Clone Wars film, which was produced as a theatrical film and from which the TV series was created.
Depending on which collection you buy, this will either exist as a stand-alone film, or be split into episodes.
Essentially you can think of Ashoka and Anakin meeting in Season 1, Episode 1.