Well, you have a few options.
1) USB Mouse. You would need to get an OTG USB adaptor (basically a female-USB-to-MicroUSB-male converter) and you just plug the mouse into the OTG USB Cable.
2) Bluetooth mouse. Get it synced to your tablet and presto!
3) Use your computer's hardware. If your computer and your tablet are on the same WiFi network or if you connect your tablet to the computer via USB, you can use Samsung's SideSync app, which will let you share your computer's mouse and keyboard with the tablet, letting it act sort of like a virtual extra screen. Now, for phones, this app also lets you mirror your device's screen on the computer, but I'm not sure if this feature is also available for tablets, I haven't tried it.