u/Jumpy-Scarcity-7512

I am just about to set up a roth IRA and start depositing funds. I have heard people on here talk about only needing VOO and QQQM (Idk what the M means compared to QQQ). However in addition to those two ETF's mentioned above, I was recently also told I should allocate funds for VTV and VTI (so total funds spread evenly across all 4). I would love some help just understanding what and why, these 4, or any amount, are recommended. Thank you all!