Here is a post with instructions:
https://steemit.com/witness-category/@timcliff/steps-for-setting-up-a-witness-node-the-manual-way
Regarding this "Reports of the Witnesses", it is a weekly report of the witness activities. If you create a post announcing your witness campaign, or post a witness update, I will include it in the report. I scan the #witness-category tag to look for relevant posts.
Writing of instructions, is there a way to undo a resteem?
No, there is not.
Had it been my own post, I could at least delete it.
You can delete it until it gets an upvote, then it can only be edited.