Do senators make laws in the Senate?

Yes and No:

The Senate is one of the the houses that make up the bicameral Congress. As such for a bill to become law it requires the approval of at least 51 Senators. However the bill will not automatically become law. This is because it also needs the support of the House of Representatives (lower chamber) and as such if the support is denied then the bill can not become law.

Furthermore, even if the bill does gain the support of both Houses, it is the President who holds the power of promulgation and as such can decide to veto the bill. Having said this, this veto can be overridden if it has the support of at least two thirds of Representatives and Senators.