Rookie investor help

Hi all, new to this and am hoping for a little advice. I am wanting to take the buffet approach to investing as a new investor. You know the whole "of you'd invested $10k 20 years ago you'd be rich by now. I recently came into a little money and was waiting for Berkshire to hit 420 and buy like 20 shares of it and 20 of xlf. Is this wise?

I am wanting to focus on investing primarily in etfs. Any thoughts or advice are appreciated

Edit: I have $50k and don't want to fuck this up. Not trying to time the market and make a million (unless you have suggestions in which case I'm all ears) just want to do the responsible retirement thing.

I turn 40 this year and got lucky/ blessed with this windfall and I keep getting the feeling if I do this right ill be straight 20 years from now.

Thank you everyone for the suggestions.