I think her answering only with technical questions about the computer means she's just wanting info about the computer. She's a big girl. If she has further questions for you husband about the computer, she'll email about them when she can. If she doesn't get around to it today, that is her problem. I suspect if she gets home tonight and needs your husband's help with her computer, she'll email those questions.

I don't see this as anything to do with you and boundaries quite honestly. Email the instructions and let it be. If she needs more input, she can email those questions. No need to ask her about boundaries concerning this as you have no need to email her after hours about this unless she emails a question to you first.

Don't continue to email her about this. She'll contact you if she needs to about the computer.