I want to start SIP but I am not sure where to start ? How should I invest and where should I invest ? My budget is 25k per month.

Decide on: Why do you wanna do SIP? A. Short term(<5yrs) gains B. Long term corpus

Now select which sector would give you results in the above duration.

If you aren't confident in your own analysis, rely on ETPrime/ Moneycontrol/your own bank's app.