I've lifted a patio slab that was rocking when stepped on and also had some broken pointing. There's loose sand underneath which I've piled to one side and it was covering a bit of a cavity. I'm wondering whether to pat the sand back down and just put some large blobs of sand and cement mix in each corner? Do I need sharp sand, building sand, or some other type of sand, and would you recommend mixing 4 parts sand to 1 part cement? That's what I've been seeing on YouTube videos. And 3 to 1 for mortar joints? I also want to fill a small hole in my front wall.next to the window frame. How much sand and cement do you think I should buy? I'm going to go to builders depot they're normally pretty inexpensive. I'll need a bucket. And I'll need a trowel but I don't know what size. And should I use a piece of old hose to smooth out new pointing or just fill the gaps around the slab and brush away excess?