Hey

previous year question papers are available on many sites but since AIIMS is is conducted in an online mode now it is difficult to get a solved paper of 2018 AIIMS

but I found a link

https://www.google.co.in/amp/s/admission.aglasem.com/aiims-mbbs-2018-question-paper-with-answers/

if this helps you because this is very much based on the same pattern

practice a lot of questions from previous year paper of AIIMS to get an idea of the kind of questions that are asked .

AIIMS is a difficult exam but hardwork & smart study are the key to success for this exam.

good luck!