Hii Pinki,

What you can do is appear for a lot of mock tests by downloading sample papers from various sites or even online by various coaching institutes. I am attaching a link to sample papers which are based on the same pattern on which the actual papers are made on and then you are done and well prepared for the entrance test. Link to sample papers- https://university.careers360.com/articles/bhu-uet-sample-papers

When the Books are back in stock you can buy them and practice more sets of sample papers and other questions given in the books.

Appearing for mocks is really important as it will improve your rank and will give you the idea of how the actual paper might be and the level of it.

HOPE IT HELPS,

THANKS.