Undoing things

Because rewind button is host-only and can be finicky (also interferes with second game on the table if there is one), undoing bad things may seem tricky. But it's not. Once you get the hang of TTS controls and how X-Wing works there, nothing should take you more than like 30 seconds to fix. Here's tips on that.
You need to know what "performing commands" means, see Doc: Commands.

My ship is not where it should be!

No matter if this is a result of wrong move performed or someone yanked it accidentally, do the 'q'/'undo' command. That essentialy recalls ship saved positions - save occurs every time an automated move finished or 'keep' command is used.
If you go too far back using 'q'/'undo', 'z'/'redo' does what you think it does. You can fiddle with these commands as much as you like, nothing will be un-undoable.

I've deleted a pilot/upgrade card!

Use the Item Browser (Doc: Squad Building) to search and spawn the item you lost.

I've deleted one of the assigned dials!

It should be restored automatically with a message printed to chat.

I've deleted a ship!

This is the most work-intensive case. Make sure your ships aren't unlocked the next time and don't delete them when they are destroyed - just drag it off the playmat.
Use the Item Browser (Doc: Squad Building) to search and (re)spawn the ship you've lost. Then follow the "I've deleted a dial" case here to reassign all dials (including the newly respawned ship model).
Then look in the chat for a message saying something along the lines of "XXX ship model has been deleted - use 'restore#N' command to access hist last state". Perform the "restore#N" command on respawned model (supplying a listed number for the N) to plop it back where the deleted ship was last seen at and you're ready to continue playing.