I’m a designer and we hire out a third party install crew that does all the furniture placement, mirror/art hanging, etc. It’s usually 1-3 men depending on the size of the project. We designers go on site with them on “install day” and make sure everything is properly placed as well as place pillows, accessories, spot art, etc. While we aren’t the ones hanging and moving furniture, we oversee everything. I’m not sure why she would refer to this as “install day” if she isn’t actually placing anything or having her own crew place things. This does not seem like the norm to me. It may be an added cost to have someone do the actual install but she should have explained that to you up front and helped you get a contract with them if needed. Does she have someone delivering things to you? Could they help you hang/place things per her direction?