As with all structures, there is a foundation and pillars to make it strong. This structure in Islam is called Al-Aqeeda. In Islam, the foundation is the belief and worship of One God (exalted is HE), Tawheed. It is supported by five pillars
Al-Aqeeda is the whole of Islam wrapped up into one word. The word Islam means submission to Allah, exalted is HE; whereas the word Al-Aqeeda covers many things. Each of these areas can be summarized up as Tawheed, Prophet Muhammad (peace and blessings be upon him), The Glorious Qur'an, Mi'raj, Kauthar, intercession, the covenant, Taqdir, throne and chair, status of Ibrahim and Musa, books of Allah (exalted is HE), Muslim and Mu'min, messengers (May Allah be pleased with them), and some other more general things. (Muslim Creed, 1998) This is a rather large subject and will have to be explained over time. The best way to start is in the foundation of Islam, Tawheed
Tawheed consists of three important parts. The first part is maintaining the Unity of Lordship. It is called Tawheed ar-Ruboobeeyah. The second is maintaining the unity of Allah's (exalted is HE) names and attributes. This one is called Tawheed al-Asmaa was-Sifaat. The third part of Tawheed is maintaining the unity of worship. This one is called Tawheed al-'Ebaadah. (Philips, MSA)
The five pillars are worship of One God (exalted is HE), Allah (exalted is HE), and belief in the Prophet Muhammad (peace and blessings be upon him); prayers, salah; charity, zakat; fasting the lunar month of Ramadan; and traveling for the sake of God (exalted is HE), hajj
Reference:
Abu Ameenah Bilal Philips. The Fundamentals of Tawheed (Islamic Monotheism). Provided by MSA. Retrieved on 03/28/07. from
http://www.usc.edu/dept/MSA/fundamen.../abutaw_1.html Abu Ja'far Ahmed Bin Muhammad Bin Salama Al~Tahawi. The Muslim Creed (Al-Aqeeda Al-Tahawiya). Notes from Al-Shaikh Abdulaziz Bin Abdullah Bin Baz. Translations by Suhaib Hasan Abdul Ghaffar. Provided by International Islamic Publication House, 1998. P.O.Box 55195- Riyadh 11534 – Saudi Arabia
Basic Structure of Islam 
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