Here are the Adventist fundamental belief statements that deal with the questions you have asked. You can read more at
http://www.adventist.org/beliefs/fundamental/index.html.
1. Holy Scriptures:
The Holy Scriptures, Old and New Testaments, are the written Word of God, given by divine inspiration through holy men of God who spoke and wrote as they were moved by the Holy Spirit. In this Word, God has committed to man the knowledge necessary for salvation. The Holy Scriptures are the infallible revelation of His will. They are the standard of character, the test of experience, the authoritative revealer of doctrines, and the trustworthy record of God's acts in history. (2 Peter 1:20, 21; 2 Tim. 3:16, 17; Ps. 119:105; Prov. 30:5, 6; Isa. 8:20; John 17:17; 1 Thess. 2:13; Heb. 4:12.)
2. Trinity:
There is one God: Father, Son, and Holy Spirit, a unity of three co-eternal Persons. God is immortal, all-powerful, all-knowing, above all, and ever present. He is infinite and beyond human comprehension, yet known through His self-revelation. He is forever worthy of worship, adoration, and service by the whole creation. (Deut. 6:4; Matt. 28:19; 2 Cor. 13:14; Eph. 4:4-6; 1 Peter 1:2; 1 Tim. 1:17; Rev. 14:7.)
3. Father:
God the eternal Father is the Creator, Source, Sustainer, and Sovereign of all creation. He is just and holy, merciful and gracious, slow to anger, and abounding in steadfast love and faithfulness. The qualities and powers exhibited in the Son and the Holy Spirit are also revelations of the Father. (Gen. 1:1; Rev. 4:11; 1 Cor. 15:28; John 3:16; 1 John 4:8; 1 Tim. 1:17; Ex. 34:6, 7; John 14:9.)
4. Son:
God the eternal Son became incarnate in Jesus Christ. Through Him all things were created, the character of God is revealed, the salvation of humanity is accomplished, and the world is judged. Forever truly God, He became also truly man, Jesus the Christ. He was conceived of the Holy Spirit and born of the virgin Mary. He lived and experienced temptation as a human being, but perfectly exemplified the righteousness and love of God. By His miracles He manifested God's power and was attested as God's promised Messiah. He suffered and died voluntarily on the cross for our sins and in our place, was raised from the dead, and ascended to minister in the heavenly sanctuary in our behalf. He will come again in glory for the final deliverance of His people and the restoration of all things. (John 1:1-3, 14; Col. 1:15-19; John 10:30; 14:9; Rom. 6:23; 2 Cor. 5:17-19; John 5:22; Luke 1:35; Phil. 2:5-11; Heb. 2:9-18; 1 Cor. 15:3, 4; Heb. 8:1, 2; John 14:1-3.)
5. Holy Spirit:
God the eternal Spirit was active with the Father and the Son in Creation, incarnation, and redemption. He inspired the writers of Scripture. He filled Christ's life with power. He draws and convicts human beings; and those who respond He renews and transforms into the image of God. Sent by the Father and the Son to be always with His children, He extends spiritual gifts to the church, empowers it to bear witness to Christ, and in harmony with the Scriptures leads it into all truth. (Gen. 1:1, 2; Luke 1:35; 4:18; Acts 10:38; 2 Peter 1:21; 2 Cor. 3:18; Eph. 4:11, 12; Acts 1:8; John 14:16-18, 26; 15:26, 27; 16:7-13.)
6. Creation:
God is Creator of all things, and has revealed in Scripture the authentic account of His creative activity. In six days the Lord made "the heaven and the earth" and all living things upon the earth, and rested on the seventh day of that first week. Thus He established the Sabbath as a perpetual memorial of His completed creative work. The first man and woman were made in the image of God as the crowning work of Creation, given dominion over the world, and charged with responsibility to care for it. When the world was finished it was ``very good,'' declaring the glory of God. (Gen. 1; 2; Ex. 20:8-11; Ps. 19:1-6; 33:6, 9; 104; Heb. 11:3.)
7. Nature of Man:
Man and woman were made in the image of God with individuality, the power and freedom to think and to do. Though created free beings, each is an indivisible unity of body, mind, and spirit, dependent upon God for life and breath and all else. When our first parents disobeyed God, they denied their dependence upon Him and fell from their high position under God. The image of God in them was marred and they became subject to death. Their descendants share this fallen nature and its consequences. They are born with weaknesses and tendencies to evil. But God in Christ reconciled the world to Himself and by His Spirit restores in penitent mortals the image of their Maker. Created for the glory of God, they are called to love Him and one another, and to care for their environment. (Gen. 1:26-28; 2:7; Ps. 8:4-8; Acts 17:24-28; Gen. 3; Ps. 51:5; Rom. 5:12-17; 2 Cor. 5:19, 20; Ps. 51:10; 1 John 4:7, 8, 11, 20; Gen. 2:15.)