i just put my os on sdd but when i try to install things like firefox and google chrome they go straight to my ssd and i dont want it to fill up quickly because its only 64gb how do i do it that everything i download goes on the hdd
Generally you need to select the customer install option on whatever program you are trying to install. It will then show you the install path and let you change it to wherever you would like the program installed. Most programs will default to C:\ if you do the standard install process.
It is depending on the program you install.
Some programs let you chose where you want to install them some others not.
As for your example firefox, after downloading run it as administrator,
it will start extracting.
After the extract the first page of the installer will pop up where it says
that you will istall firefox, just press next since most of the times there are
no options at the first page of the installers.
On the second page you will notice that you have to make a decision
between Typical installation or custom installation.
In your case check custom and press next.
Now you should notice that on the 3rd page of the installer there should be
an instalation directory for example C:\Program Files\Mozilla Firefox\
you can change it if you press browse and than navigate to your second hard disk.
After this just finish your installation just as usual.
When you run the installer, almost always one of the first options to Standard or Custom install, select the bullet for Custom install. You will need to know what the driver letter is for the HD you want to install things to though.