New to Hijab - Looking for tips

As-salamu alaikum, I’m a recent revert to Islam, and I currently only wear the hijab in the mosque and during prayer. However, I’m practicing wearing it more often because I want to gradually start wearing it full-time. I recently bought a chiffon hijab. While I’m comfortable with modal and jersey fabrics, chiffon has been quite a challenge for me, even though I love how elegant it looks. I tried securing it with pins and magnets, and at first, it seemed fine. But when I was in the mosque, some of the pins fell out during prayer. I had to blindly pin them back into place. In the tutorials I’ve watched, hijabis seem to pin their hijabs so quickly and effortlessly. I’m not sure what I did wrong, but several pins came loose. Thankfully, I had an undercap underneath, but half of my hijab slipped, which was really uncomfortable and a bit embarrassing. Another issue I’m having is that my undercaps keep slipping. I tried securing them with bobby pins, but that didn’t seem to help either. Do you have any idea what might be causing this? I’d be so grateful for any tips.