Package compatibility

[fcs]

I apologize if this is a dumb question, but how does compatibility work when installing packages? I've been able to install packages on my new Pinebook Pro (Ubuntu MATE) using either apt or the .deb package manager. Every now and then, some of these installs fail. My question is what is required for an Ubuntu application to be able to run on the Pinebook Pro? Did someone have to specifically compile it for the right CPU architecture? And if that is the case, are we significantly limited then on what can run on the Pinebook Pro?

If there is a good reading material that explains this in detail, I'd appreciate a link or if you point me in the right direction.

Thank you!