No need to worry! I would recommend you to go through the instructions of SRMJEE again and follow each steps patiently and sincerely & I think your problem will get solved. As you register your slot you will get the option for your mock test.

For SRMJEE slot booking instruction visit the link provided below:

https://www.srmist.edu.in/content/slot-booking-instructions

I hope this answer helps. All the very best for your future endeavors!