I am an EE student and im trying to design a sub1GHz system

Do you have an overall spec for what you want to implement? From this it's hopefully a bit easier to point to where you should start.

Im not sure what you mean by overall spec.

You are going to implement a RF system.

have you though something about the following:

- Range (output power, sensitivity, link budget etc)

- Frequency

- Datarate 

- Do you want a transceiver + MCU or a wireless MCU?

etc.

I could give you a lot of links etc but first you have to sit down and write a spec of what your "box" is going to do. After that we can look into what that "box" should contain.  

Range is going to have to be 100km, its a rocket so its going straight up, so its 100k line of sight, not 100k over the horizon.

Im thinking somewhere in the 430MHz range for frequency.

Datarate will need to be fairly high 1mbps+, as it will have not only telemetry data but a 720p video feed.

It will require a transceiver + mcu, id imagine at least, considering the distances involved.

Not too easy spec. If you play with http://www.ti.com/tool/RF-RANGE-ESTIMATOR you will see that achieve the range you want to use with high datarate is not straightforward. You also have to look into the max output power allowed to send on the band you want to use. 

So I messed around with the tool a bit and its designed more for over the horizon transmission, is there a tool more suited to my application? Also can you give me an overview of what simple link is, im still not sure what exactly it is and how to implement it, thanks.

So its a software program? like CAD?

No, it's a product platform as the link I sent you state.