Hello Raghu ; preparatory list is made for sc,st and pwd category students.One can get admission from preparatory course list on the following conditions :

1.The seats reserved for respective category are  vacant(SC category seats for you).

2. Candidates have not accepted a seat in the preparatory course earlier.

So

Hello

With your current rank in JEE Adv, it is tough to get any IIT. You can get an IIT if you were female OBC NCL. I am including the list of IITs that you might get. 

• IIT Bhubaneshwar - Metallurgical and Material Engg. (Female only)
• IIT Bombay - Bachelor

Brother, it would be easier for me to guide you, if had told your JEE advanced marks.

Though, from your category rank, it appears not only you have qulaified JEE advanced but you have managed to get a seat at new IIT's.

So, I would recommned you to explore your

Hello Pavan,

Since you have about 1k rank in JEE Adv in ST category, I am sorry to say but no you won't be eligible for any IIT in CSE Branch.

With your current rank, you may get a few other branches in the bottom tier of IITs. As per

Hello!

You have to arrange them in order. If you are really confused about all three of them, then i would suggest you to go as per the NIRF rankings. Along with it, consider which place would be more reachable for you and many such things. 

You can't fill first

Hello 

You have got a decent rank 

Getting IIT is tough as cutoffs are very high as per previous year statistics 

Many get closed at 150 rank pwd general

But you should try for nits 

Nit Andhra Puducherry  Jamshedpur are good 

You can get non circuit branches here 

Hello 

Congrats you have got a very good rank 

You will be an iitian 

Coming to the cutoffs based on previous year statistics

Top 3 iits Bombay Delhi and Madras 

Bombay closing rank is 139 for civil engineering at last round 

For Delhi it is 170 

For Madras it is

Dear aspirant, 

It changes every year. If we take an example,

In 2017:

For general it was 81

I'm providing you the link in which you will get each and every information regarding the cutoff and all the FAQ's

https://engineering.careers360.com/articles/jee-main-cutoff-marks-and-ranks-faqs

Go through this link..!!