kerbal space program has the desire to kill me.

[~>APOLLOSMUDGE123<~]

I can't seem to attach satellites to the interior of my cargo ship, and the cargo ship has the exact amount of space for it to be in; I hope KSP doesn't make me have to load cargo into the ship manually. 

[purpleivan]

If you post a screenshot of the craft that you're working on it will help people to understand the problem that you're having.

[Geonovast]

If the problem you're having is that it's insisting on attaching radially and ignoring the node in the cargo bay, hold alt (if you're on Windows) to disable radial attachment.

[Cpt Kerbalkrunch]

Impossible to know without pics but, if the sat your using is a subassembly or separate ship you're merging with the cargo ship, the root part might be your issue; which you could solve with the re-root tool. A bit more info would make it easier to help you.

Edited March 24, 2018 by Cpt Kerbalkrunch

[Geonovast]

If it's a root problem, here's a quick and dirty rundown of the re-root tool.