My baby is trying to crawl 😭

My girl turns 6 months in 4 days and had been working overtime to figure out crawling. About 2 weeks ago she lifted her butt in the air with head on the ground, now she's in crawl position but can't figure out how to push forward and she flips out when she realizes she's not moving. Meanwhile her twin brother is just hanging out and not caring about trying to crawl. Is any one else going through this stage yet? Im dreading having to chase 2 babies around 😨