Ball pythons are really not that hard if the OP has done the research. The main issues that newbies miss are not knowing what a thermostat is (thermostats are required to regulate the heat pad/heat source) and hides that aren't small enough. Keeping humidity up in a tub setup makes things much easier too (add some sphagnum moss in the hides if needed and spray it down a little)
The OP already knows to start with a tub setup, has the caresheet and setup guide, and is on this forum asking for advice, and I'm sure is prepared for the worst going into a malnourished adult rescue anyway. It's their choice and it'll more than likely be okay!