In Shrila Prabhupada's Teachings of Lord Chaitanya, there is one very important chapter called "Lord Chaitanya, the Original Personality of Godhead", which establishes the Supreme Divine Position of Lord Gauranga and explains the Gaura- as well as Pancha-Tattva. One paragraph i would like to share with You here:
"By analytically studying the five diverse manifestations of the Supreme Lord, we can come to know that Lord Sri Caitanya Mahaprabhu is the Supreme Absolute and that Lord Nityananda is an immediate expansion of the Supreme Absolute Truth. We can also come to understand that Advaita Prabhu is also in the category of the Supreme Personality of Godhead but is subordinate to Lord Caitanya and Nityananda Prabhu. The Supreme Personality of Godhead and His immediate subordinate expansions are worshipable by the other two -- namely the representation of the internal potency and the representation of the marginal potency. The representation of the internal potency, Gadadhara, represents the confidential devotee, and the representation of the marginal potency is the pure devotee. Both of these are worshipers of the other three categories, but all of them are engaged in the transcendental service of the Supreme Personality of Godhead, Sri Caitanya Mahaprabhu."
Just to add here one small observation of mine:
If You look at any picture of the Pancha-Tattva You can also see this hierarchy represented within: Lord Gauranga, the Supreme Personality of Godhead in the middle and top; on His right Lord Nityananda and Lord Advaita - the other two Vishnu-Tattvas, yet bellow Lord Gauranga because subordinate to Him; Lord Advaita at the very bottom of the right side, because subordinate to both Lord Gauranga as well Lord Nityananda; on Lord Gaurahari's left side are His two Shakti-Tattvas, Shri Gadadhara and Shrivasa Pandita, both below Lord Chaitanya because subordinate to Him (His Energies); Shrivasa Thakura below Shri Gadadhara Pandita, because representing pure devotee whereas Shri Gadadhara Pandita is representing a (topmost) confidential devotee (Shrimati Radharani), who is considered to be higher (highest).