Can you replace all parts of toilet system, I already have the parts

NEAR Atlantic Ave near Merrick Road, Lynbrook NY

Description

I have a family member that has a small bathroom with very old "guts" inside the toilet. Inside everything needs replacing, including the rubber washers that are working with the bolts that hold the top of the toilet, to the base of the toilet. Regarding the parts, I have already purchased the "easy install, Fluidmaster, Universal All in One Repair Kit". SEE PIC. Also need the toilet seat/lid replaced. I have already purchased that also. I am paying $120 cash, in Lynbrook, prefer early daytime on a weekday.