For most new researchers, lab work turns out to be more difficult and more complicated than anticipated--even with a solid background of lab classes. It takes time to gain the skills needed to be successful and learn proper technique.
If you're struggling to get a technique to work, you'll be more successful if you embrace that fact and ask for help from your research mentor. Most researchers need to work through technical challenges at some point--many of us throughout our careers. Asking for help from someone who has more expertise is so, so, so much better than trying to guess what to do.
Quick note: If you have a research supervisor definitely check directly with them and not another labmate because different researchers often have different approaches to solving technical difficulties at the bench.