The forum 'spoiler tag' is just a way to display and manage long lists of information (logs, command outputs, etc.), making it a bit easer for the reader to distinguish between the relevant description and any lengthy included data. But be selective to help the reader, so they don't have to thumb through pages of info just to get to the relevant bits, for instance if its only a few of lines then its not really required. . . but up to you.
When submitting, select the '...' on the toolbar, then position the cursor at an appropriate relevant location below the written text where you wish to locate it, then select the '
Spoiler
Insert text here
Then continue with the description . . .