It is therefore...
It is therefore, reprehensible to underestimate or ignore salat al-Jama'at, and according to the Islamic rulings, it is not permitted to keep away oneself from the salat al-Jama'at unduly, nor is it proper to abandon it without a justifiable excuse. It is further Mustahab to wait for some time until the salat al-Jama'at begins with the intention to participate in the salat, since a short congregational salat is better than a prolonged salat offered alone.
It is also better to wait for the salat al-Jama'at to be established, even if it is offered after the prime time rather than to pray alone. In fact, if a person realizes that the salat al -Jama'at has been established but he has already read his salat, it is Mustahab to repeat the prayers again in Jama'at. The Arrangement of Salat al-Jama'at The Imam of the Jama'at stands in front of those who are following him.
The followers are behind him, forming straight lines - each standing close to the other one's shoulders. As for the distance between the rows, according to Ihtiyat Mustahab, it should be just enough to allow the person to perform Sajdah. When there are only two people in salat al-Jama'at, the Imam and the Ma'mum, then it is Mustahab that the Ma'mum position himself just behind the Imam on his right side, although, he can also stand in line with the Imam.
When there are many followers, according to Ihtiyat Wajib, the followers must not stand beside the Imam , rather they must be behind him. The standing place of the Imam compared to that of the Ma'mum should not be higher than the span of four closed fingers. But the place where the followers stand could be higher than that of the Imam. Of course, the height must be reasonable enough to maintain the appearance of Salat al-Jama'at.
There must not be a large distance or obstruction between the Imam and the Ma'mum. If the Ma'mum is standing exactly behind the Imam, then his forehead in Sajdah should fall just behind the feet of the Imam. Similarly, there must not be any gap or obstruction between the lines.
If during the course of the Salat al-Jama'at, a person finds that he is distanced from the preceding line by a foot or more, then since he is isolated from the Jama'at, he should change his intention from Salat al- Jama'at to Furada' (single prayer) and continue his prayers as such.