Which logs should be looked at first?

I am coming from working with Microsoft's SCCM to working with Desktop Central. I've been put in charge of the Patch Management process and revamping it and fixing issues with it.

With SCCM, i know which logs i need to look at first to help determine where the troubles may have started and to help get issues resolved more quickly.

I was looking in the logs folder and started to go through a few, but like SCCM there are quite a few dozen logs on a machine.

Which logs are the most important to look at first for machines that are:
1. Failing patch management in general
2. That have remarks of Deployment Failed, but are listed as Healthy

I'm also curious as to what the remarks of "--" means? I have a handful that have this remark, but they are listed as healthy yet are missing patches.

Thanks.