Hey Pathan,

As an engineer, most of us used to study for a month or a week or a day before the exam. So if you are very interested to crack SSC JE exam the best way is to study every day. Devote 2 hrs every day for it and increment the time as the day passes. And this will help you to concentrate and also this will also help you to complete both syllabus. 

• Go through the syllabus mark the chapters you will start from 
• Allocate time wisely for every subject
• Solve previous year paper and Engineering paper
• give mock (At least 15 or more)

Hope that helps

all the best