My uncle falsely thinks I’m some kind of experienced stock trader and wants me to help my cousin invest money she made recently. I need help

I dabbled in crypto a small bit and my dad immediately bragged to the whole family about it; now my uncle wants me to help my cousin make investments and stuff in stocks. I'm new to crypto and completely inexperienced in stocks.

I have no idea what I'm doing. What apps should I download, what are safe all-round investments I should recommend? I don't want to look like a moron, I'm sure you guys have some base level advice right?