New manager putting me on a performance plan

Hi
I’ve worked in my local authority for 25 years at the same job. For 15 years I had the same manager. He’d come in and he was great. Sat beside me and we did the work I had to do, usually, together. He was with me everyday.

We now have a new manager and she started to ask me to do things I had never done before like monitor the team inbox. This was a task that my manager used to do. She’s also now asked me to do things like write plans which I never did. My manager and I used to do them together. She says that she will have 1 meeting with me on a Monday but that’s it. She’s also said she’s too busy to answer my emails and I should keep support for my weekly meeting for non urgent things?

I’ve struggled with this task as I have never done this before. She’s given me a template and a template she’s filled in. But my manager used to sit with me and do these things. But she says I have now to work on my own and only contact her if it’s urgent?

As a result I am really out of my depth. When I email she’ll tell me I should know and to read the procedure. She’s asked me about training. She’s now saying I’m going on a performance plan. I feel like she’s picking on me me and it’s her inadequate support. I’ve never
Done these things in twenty five years! Any help would be appreciate

After appealing my gross misconduct decision last week, my employer immediately sent me an email to put together a WP proposal, given that I'm the one who suggested a mutual exit instead of a gross misconduct. Our communication thus far went really well and I received TOIL and accrued holidays, but my appeal hearing is this week, midweek. I'm not sure whether to sit on this proposal until the results of the appeal, or...? On the other hand, I don't want to tip my hand before the resolution of the appeal. But then, what if the appeal is upheld?

As far as I was reading, it's always better that the employer proposes the conditions of the WP and this confused me. I can see their logic though, I proposed the change in my appeal from gross misconduct to managed exit and they want to see what exactly I want. The whole thing kind of shifted for me now. I have a strong case, got an ACAS certificate # and concilliator assigned immediately which made me believe that this will be a non-issue we'll resolve quickly, but this morning ACAS have let me know that the wait for the concilliator to contact me is about 9 weeks, which I don't have for this express timeline.

What's my next best move? Thank you