To start home along training you do need to cover some basics first.
Such as rules.
Can she cook anything while you are gone? No stove top/baking? Use Microwave? Can she have anything plugged in that normally isn't going? Such as a hair dryer? Washing machine? Small alliances such as a toaster?
Who can she call if she gets scared? Can she call a neighbor if she thinks something is wrong? Who can she share she is home alone with?
What if something happens to you while you're out walking and she can't reach you? You don't come home on time? What happens, plan B?
Can she be online? Texting friends? Watching TV?
Can she answer the door? If it's someone she knows knocking? Is there a safe word that the person has to say that will allow her to hear them say then she can open it to them?
Once you have through this through and decided what she can or cannot do according to where you live and who is around you then you have to give her a chance to succeed or fail. By that I mean leave her for a few minutes by going next door or down to the mailboxes, going to your car and cleaning it out with her alone in the house, this will give her a gradual initiation to hearing the house, noises that normally occur that we don't notice unless we're alone and it's quiet.
When we started letting our girl be home alone she was 10. We live on the same property as my father in law and we go clean his house and do things for him when he needs us. So we'd go to his house and let her be "alone". We were not that many feet away but she was in fact alone in the house for the first time. She heard noises and the wind and a few other things from nearby neighbors and stuff. It sort of scared her just a bit at first. So by giving her time to get used to it she was able to know she was okay.
Another thing we did, if we left the property, was to tell the neighbors. I'd call each one and let them know we were doing home alone training and if it was okay with them could we tell our girl if she got scared or something was going wrong could she call them and they always said yes.
I trust my neighbors a lot and I've known one family for nearly 24 years. The other neighbor has worked in law enforcement and has had various serious background checks and I've worked with a couple of his family members over the years. He's the best neighbor we've ever had. So I trust both of these families without doubt of any sort. If something happened to me I'd be completely comfortable with our girl going and staying with them for days or even weeks. I have a great support system in my neighborhood.
You might not know a single person in your building that you'd trust that much. That's okay too. Don't just trust them because there isn't anyone else. Do you have a best friend? A family member? That could step in and take her if something happened to you? That she could call if you're not home on time?
These are all things you have to consider and make decisions on. She is more than old enough to stay home for an hour. Some kids her age stay home all day long by themselves when school is out and mom/dad have to work. Childcare providers don't usually offer child care for kids 10 and above because they just don't have many kids that come. Once they get to middle school they don't need a babysitter. They're almost old enough to babysit other living beings.
My thought is if they're old enough to take care of others then they better be used to taking care of themselves first. And learning home alone time is an important step is self sufficiency.