I have two questions:
Once downloaded install it directly without uninstalling window 7 right?
where do I download drivers for the printers?
You don't have to uninstall anything from windows to use a printer from Ubuntu.
How to install a printer in Ubuntu can depend upon the printer brand and model. Ubuntu comes with support for many (almost all?) printers without having to download anything or install anything else.
Having said that, some printer manufacturers may make available special driver for Ubuntu/Debian systems.
After you have connected the printer to your system, or to your network, the place to start is to go to the Gear icon at the top right of your screen and choose "Printers". Then you can use the "+" button to add your printer. Details will vary depending on how the printer is connected to your computer and whether you want to share it, for example.
As Jorge suggested above it would be helpful for us to know more about your printer. You can click edit under your question to add more details.