You’ll get lots more helpful advice on the Elderly Parents board - try posting there too.
We had something similar with DF. You’ll likely receive a care needs assessment from a social worker listing what your dad needs help with - this is what the 2 visits a day will have been based on.
At the first visit, the carers should leave you their paperwork - including contact details and the care plan which details what the carers will do each visit. Have a list of questions ready for them!
Is it funded or do you need to pay?
A few practical things we’ve found useful - having all medication, clothes, wash stuff in one place so the carers can get straight to it without asking questions. Definitely get a key safe. It might feel strange having people in your home - when they’re here, make yourself scarce, let your dad build trust with them, but feel free to check in with them before they leave.
Use them as your ally - DF won’t take any notice of DM, but will listen to some of the carers. Share that with them (when you feel comfortable) and ask them to be your voice on matters if necessary.
Things like making a cup of tea, or little things like changing socks/fetching slippers etc are all part of the carer’s role. It took us a while to get used to that - DM thought she was helping by doing those things while the carer was there, but it’s important DF learns to ask the carers for what he needs.
Finally, learn to live flexibly/in a bit of chaos for a while. They usually give you a 2 hour visit window and can arrive at any point in that. You’ll also likely have different carers throughout the week, your dad might take to some quicker than others.
Good luck!