Where to invest?

Me and my boyfriend is planning to visit Europe for a 10 day international trip somewhere in 2031 and is planning to invest next month onwards.

We have our pension funds, emergency funds, liquid funds, health and vehicle insurance and long term mutual funds all set up and is now planning to invest around 15k per month into our medium term goal of travelling to Europe.

But I am unsure how to move forward. Any one can help me in this?