Help with cutting/transparency on design in illustrator

Hi, I am struggling on what seems like the most simple thing. It's kinda of hard to explain over text but I have my design and I want all of the lines to match up evenly with the half circle. I tried the clipping mask and also transparency thing to crop the edges of the lines with another half circle lined up evenly and I cannot for the life of me figure out how to cut them. I attached photo below of my design and then also the one with the other half circle to show the edges that I want cut off. I hope this makes sense and wish I had a friend in person that knew illustrator who I could explain this to for help, it seems so simple but I am just not very familiar with the program. Any help would be greatly appreciated!