To get admission in Amrita you will have to crack AEEE exam and for SRM, you will have to crack SRMJEE. Also, the application window for both of them is open so you can apply there. To know more about the same in details, you can go through the below links -

https://engineering.careers360.com/articles/srmjeee

https://engineering.careers360.com/articles/aeee

And if you talk about the preparation strategies then you can consider below tips -

1. If you are IIT-Jee aspirant also then you will find AEEE and SRMJEE relatively easy so it is advisable to get good preparation material and make NCERTs your primary resource as these will be helpful to make all the concepts strong and clear.

2. In AEEE, mathematics consist more weightage so it is advisable to prepare accordingly and for that keep NCERTs your priority and then RD Sharma would be good as a reference book and for SRM also, make a hobby to practice maths questions daily and memorize the formulas on daily basis.

3. Cover all important questions and topics through sample papers and previous year papers and keep practising.

4. Once you are done with the syllabus and previous year papers then next step to do for both is online mock papers so I would suggest you to practice topic and full length mocks as these would be helpful for you to know the exact paper pattern and important questions as well and you will get to know where all you are still lacking and what all strong areas you have and this will also teach you time management skills.

Good Luck!!!