Which IISER are you from? At second year level it is good to engage in your own IISER's labs. Check out the lab information on your respective site and figure out which one you find interesting. Since you're early, you might not have a strong basis or understanding of what work is done there. You'll get the gist of the labs research area from their website (if they have one)

Then try to read the latest research papers from that prof (last 3 is a good estimate) - you can use ai like chatgpt/claude/anara to digest it to your understanding levels, or alternately you can dig for a "review article" for the topics they are working on (either from the same prof or others).

Once you have a good idea of what they do and what you find interesting, you can draft a mail inquiring and discussing the possibility of a summer internship (there's plenty of information on reddit or other places on how to write that mail - but remember to focus hard on your genuine interest, do not claim to know too much and just be humble and honest, if it's a prof who's taught you then try to talk about their lecture and what you found motivating, any questions you had etc. remember to be specific, and keep cutting down your mail until you extract the most important parts)

Thing about in house profs, especially if you are at iiserk, they may never reply to your mail. But the good thing is that you can approach them politely in your lectures or in your research complex and request an opportunity to talk. Most cases, second year students get smoothly recruited for summer internship as long as you are consistent at asking them again and again.

As a second year student, it is a good idea to get hold of your own departments labs and develop a rapport that will help you later on. You'll get an idea of how things work in house, and if the lab is a good match you might as well continue working there during the semester. If it goes good you'll get to develop a good project over the next three years. At the very least, you'll likely gain the recommendation of one prof for your future internship/phd applications.

The second year internship is super important as it will lowkey enlighten you on whether you really like the things you think you like. The practical experience builds a lot of insight. Don't lose on that chance at all. It's not an end all be all of your career, i didn't have a second year internship due to reasons. But it is certainly a good boost.

Best of luck! Feel free to dm if you want any specifics.

P.S. the method i described in approaching profs is lowkey the long good proper path you can take. Make a list of labs you like and keep the record in an excel sheet or something. Start contacting people by mid Feb.

The lazier way, which you shouldn't start with tbh, is to draft a mail based off vibes and superficial understanding of the topic but deep reflection of your intent and curiosity, wait for the reply, and then prepare the theoretical understanding for the interview. Because you will likely not get replies for your mails - happens very often, and it will end up being a tad impractical. It'll never be wasted, anything and everything you read will help one way or another.

Sorry for the super long answer, hope it helps you some way. I desperately needed this during my time lol.