Let's talk about the town meeting first. Whether in Greece or Rome, it is the highest authority (at least in name). Theoretically, it enjoys all the powers of the country, but it can also decide any problems of the country. It has different powers in different periods, which is determined by the strength of different consuls. Citizens' assembly will be controlled by the rulers to varying degrees, because for civilians who are not rich enough in knowledge, it is easy to be deceived and become rubber stamps under the condition of insufficient information. It may be more similar to the National People's Congress, with the highest power, but the interval between meetings is long and there are many delegates, and the proposals are put forward by the rulers.
Let's talk about the Senate. The Senate is more similar to the executive body of the highest authority, that is, the Standing Committee (although it has no subordinate relationship with the General Assembly). It has relatively frequent meetings and more free meeting forms, so it has the power to decide the daily operation of the country, and I think this is actually the real power, because many big issues discussed by the citizens' assembly are more similar and directional, and in fact it will do so if it doesn't decide. Just regard the assembly as a procedure to legalize it. The resolution of the Senate is not as high as that of the parliament (it is not a law), but it is more similar to an executive order (red-headed document). Contact with life will know. Although the legal status is higher, the effectiveness of the law is probably higher. What's more, the members of the Senate are all nobles or military strongmen with higher status. They have more resources than civilians, so their will is easier to realize.
Finally, talk about their relationship. The two are not unified, the status of the citizens' assembly is higher, and the Senate is more powerful. Theoretically, the citizens' assembly also has the right to veto the resolution of the Senate. In other words, when there is a contradiction between the two, the will of the citizens' assembly should take precedence. Historically, there are many contradictions between the two. Judging from the situation at that time, the citizens' assembly prevailed for a short time, but the final result ended in the Senate's victory. For example, Gracchus's reform was supported by the Civic Assembly at that time. The Civic Assembly vetoed the filibuster resolution of the Senate many times, but in the end, the Senate launched a coup with its great energy and resources, which made the reform aborted. So my feeling is that the citizens' assembly is nominally the highest organ, but its actual power is not enough. The Senate is the permanent decision-making body in the daily operation of the country and has the highest power in fact. I hope I can help you.