If you get some in your hive-engine wallet, just click that button that looks like a lock and enter how much you want to stake, which is the same thing as powering up.
You can get some here: https://hive-engine.com/trade/PEPE
And you can get some free tokens including maybe PEPE here: @tokenfaucet
I think the PEPE token founder still rewards powered up #PEPE but I think there was some talk about changing the amount. In any case, I just powered up 5000 PEPE to your account so you can see if you start getting rewards for that powered up PEPE.
Have a nice day! :)