The senate is a group of 300 men who help with lawmaking. These people are Patricians (wealthy) and have to be men! They didn't have the highest role in roman republic but they did have an enormous one.
The assembly is a large group of people from anicent rome and they took part in awmaking, they worked together to decide on new laws and ways of living in anicent rome.
A protest is a way to peacefully prove your opinion or thoughts about a topic. For example the plebeians used a protest to make the patricians to make changes to the way of life for it to become more fair. They all got together and marched right outside of the city and camped on a nearby hill. Eventually the patricians accepted their demands and changed the way ancient rome was governed.
Tribunes were a group of elected officials in ancient rome. They were the officers of the roman army and led it through times of war. They were commanders of the army and made all the important desicions such as battle formation, where to strike, tactics, ect.
After the plebeians protest one of their demands was all the laws of rome was to be written down on tablets so the Patricians wouldn't change them off of a whim. They were called the 12 tables and were put up on a wall, 12 clay tablets with all the laws written all over for everyone to see.
Finally the plebeians were allowed to particapate in governmental issues such as being part of the senate, or the assembly, and they got to have a say in government. Last but not least one of the two leaders of rome HAD to be a plebeian.