Simulator Update
This update makes it much easier to simulate your projects. Compiling with quartus can take a long time, so it is very useful to simulate programs in order to capture errors and check if everything works as expected.
Also it is possible to make signals visible that you wouldn't be able to see by just trying your program on your FPGA because of quickly changing signal states. The VHDP IDE assists you creating .do files that you can load with ModelSim.
You can learn how to use it here
Simulator
Install
You can try the new update by using the built-in update manager or manually installing it from here