I have four subjects in one class how can I teach each group in 90 minutes? How should I organize my classroom
This all depends on what the subjects are you are teaching. The most important aspect is to find out how much overlap there is between subjects. If you have reading and social studies, teach reading strategies with the social studies book. Find math problems that are relevant to the other subjects.
What this does is help students learn that all of the subjects you are teaching are related to each other. What this takes is extra planning in the beginning, because you need to make sure you are setting up your formative and summative assessments in ways that are for the learning objectives of each subject, so you can disaggregate the data. If you set up the work the students do in such a way that they are able to move from one subject to another without saying to themselves, "this is math, this is science..." it would be a bonus.