You need to forward a port from your router to your desktop's ip.
For example, if your desktop's ip address is 192.168.1.101 then you need to forward a port of your choice (let's say 5678 as an example) to port 3389 on 196.168.1.101
so it'd be something like this, depending on your router's configuration
External Port IP Address Internal Port
5678 192.168.1.101 3389
Then when you want to connect from outside the network you point to your RDP client to [your public ip]:5678
Or just install TeamViewer
google to the rescueyeah im using a public network in my dorm. how do I obtain the ip address?
You need to forward a port from your router to your desktop's ip.
For example, if your desktop's ip address is 192.168.1.101 then you need to forward a port of your choice (let's say 5678 as an example) to port 3389 on 196.168.1.101
so it'd be something like this, depending on your router's configuration
External Port IP Address Internal Port
5678 192.168.1.101 3389
Then when you want to connect from outside the network you point to your RDP client to [your public ip]:5678
Or just install TeamViewer