There is plenty of information on Ascended Masters available in books and the Internet too. I recommend Doreen Virtue's Archangels and Ascended Masters: A Guide to Working and Healing with Divinities and Deities. This is an excellent reference book. The Summit Lighthouse website also has informative pages about Ascended Masters. Click here for their site.

Ascended Masters have lived on Earth and, through their series of lifetimes, have liberated themselves from the karmic wheel and no longer need to incarnate; hence, they are "ascended." Because of their earthly incarnations, they have a profound understanding of our problems and issues. Jesus, Saint Germain, Kuthumi, Kwan Yin, Sanat Kumara, and Mother Mary are just a few of them. As with any other spiritual teacher, each Ascended Master is associated with specific abilities, knowledge, and attributes and they belong to our spiritual support team too.

If you are feeling attracted by a determined colour that might indicate the Ascended Master who is working with you.
For example:
Saint Germain - violet Jesus - red Kuthumi -yellow, golden Mother Mary, Archangel Michael - blue Rowena, Lady Nada - pink Djwal Khul - emerald green