I'll try to explain as best I can, though I'm not 100% certain I'm answering your question. Btw, have you seen the wiki? http://wiki.tdsm.org/index.php?title=PermissionsX
Warp is part of essentials right? I'm not sure if that has nodes for use in a permissions plugin. Either way...
If you want default users to have warp, but nothing else. Just add the warp node to the default group but remove all other nodes. Any node that isn't added to the user or group they are a part of, will not be allowed. You can also add extra nodes to a specific user to give them a bit more than the other users also a part of that group, or just add them to another group.
If you are misunderstanding nodes, nodes are commands. Nodes are just what are used to specify commands inside the permissions system. So instead of doing xgroupperms addperms Default warp, you need to specify usually the plugin name followed by a period before the command name like xgroupperms addperms Default essentials.warp. Take a look at the list of nodes for tdsm
specific nodes, if plugins have nodes, they 'should' be noted on the plugin page, though that may not always be the case.
Hope that clears it up, if not, don't be afraid to ask more questions,
this is the place to do it
EDIT: Actually I just realized I'm not replying to the permissions x thread heh
. So if you have more questions, just ask on the plugin thread if it's about this. Maybe DeathCradle or someone else who's watching that thread will chime in if they know the answer.