Butterfly 1 ji
At the risk of sounding sarcastic, the best way to answer your question is to start on Page 1 of SSGS, and proceed from there.
The Guru Granth begins with the Mool Mantar (Bhai Manmohan Singh translaiton).
1.
ੴ ਸਤਿ ਨਾਮੁ ਕਰਤਾ ਪੁਰਖੁ ਨਿਰਭਉ ਨਿਰਵੈਰੁ ਅਕਾਲ ਮੂਰਤਿ ਅਜੂਨੀ ਸੈਭੰ ਗੁਰ ਪ੍ਰਸਾਦਿ ॥
Ik▫oaʼnkār saṯ nām karṯā purakẖ nirbẖa▫o nirvair akāl mūraṯ ajūnī saibẖaʼn gur parsāḏ.
There is but one God. True is His Name, creative His personality and immortal His form. He is without fear sans enmity, unborn and self-illumined. By the Guru's grace He is obtained.
2. Then Japuji Sahib refines Guru Nanak's cogniznance of our Satguru. There are 38 pauries altogether. Here is only one that speaks to the nature of the Sat.
Guru Nanak even says, "Millions give millions upon millions of descriptions and sermons regarding God." In Japuji Sahib we are hearing about it from Guru Nanak himself. Why have a middleman do it for you?
ਗਾਵੈ ਕੋ ਤਾਣੁ ਹੋਵੈ ਕਿਸੈ ਤਾਣੁ ॥
Gāvai ko ṯāṇ hovai kisai ṯāṇ.
Who can sing His might? Who has power to sing it?
ਗਾਵੈ ਕੋ ਦਾਤਿ ਜਾਣੈ ਨੀਸਾਣੁ ॥
Gāvai ko ḏāṯ jāṇai nīsāṇ.
Who can sing His bounties and know His resplendent effulgence?
ਗਾਵੈ ਕੋ ਗੁਣ ਵਡਿਆਈਆ ਚਾਰ ॥
Gāvai ko guṇ vaḏi▫ā▫ī▫ā cẖār.
Some chant the Lord's beautiful excellences and magnificences.
ਗਾਵੈ ਕੋ ਵਿਦਿਆ ਵਿਖਮੁ ਵੀਚਾਰੁ ॥ ॥
Gāvai ko viḏi▫ā vikẖam vīcẖār.
Who can chant God's Knowledge, whose study is arduous?
ਗਾਵੈ ਕੋ ਸਾਜਿ ਕਰੇ ਤਨੁ ਖੇਹ ॥
Gāvai ko sāj kare ṯan kẖeh.
Some sing that He fashions the body and then reduces it to dust.
ਗਾਵੈ ਕੋ ਜੀਅ ਲੈ ਫਿਰਿ ਦੇਹ ॥
Gāvai ko jī▫a lai fir ḏeh.
Some sing that God takes away life and again restores it.
ਗਾਵੈ ਕੋ ਜਾਪੈ ਦਿਸੈ ਦੂਰਿ ॥
Gāvai ko jāpai ḏisai ḏūr.
Some sing that God seems and appears to be far off.
ਗਾਵੈ ਕੋ ਵੇਖੈ ਹਾਦਰਾ ਹਦੂਰਿ ॥
Gāvai ko vekẖai hāḏrā haḏūr.
Some sing that He is beholding us just face to face.
ਕਥਨਾ ਕਥੀ ਨ ਆਵੈ ਤੋਟਿ ॥
Kathnā kathī na āvai ṯot.
There is no dearth of persons who dwell upon the Lord's discourses.
ਕਥਿ ਕਥਿ ਕਥੀ ਕੋਟੀ ਕੋਟਿ ਕੋਟਿ ॥
Kath kath kathī kotī kot kot.
Millions give millions upon millions of descriptions and sermons regarding God.
ਦੇਦਾ ਦੇ ਲੈਦੇ ਥਕਿ ਪਾਹਿ ॥
Ḏeḏā ḏe laiḏe thak pāhi.
The Giver continues giving but the recipients grow weary of receiving.
ਜੁਗਾ ਜੁਗੰਤਰਿ ਖਾਹੀ ਖਾਹਿ ॥
Jugā juganṯar kẖāhī kẖāhi.
All the ages through the partakers partake of His provision.
ਹੁਕਮੀ ਹੁਕਮੁ ਚਲਾਏ ਰਾਹੁ ॥
Hukmī hukam cẖalā▫e rāhu.
The Commander, by His command, makes man walk on His path.
ਨਾਨਕ ਵਿਗਸੈ ਵੇਪਰਵਾਹੁ ॥੩॥
Nānak vigsai veparvāhu. ||3||
O Nanak! the carefree Master makes merry.
Satguruji defies description, yet we can know him. These are a start, and everything to follow in Sri Guru Granth Sahib Ji builds and increases upon these words. Good luck in your project.
Any forum member who has concerns with the given translation need post his/her own preferred translation to clarify differences in understanding. 
