How do you snake a line? A main line? Hopefully you would snake the main line from a clean out. A clean out is the opening that you have with the lid and it would normally be on the outside of your subject property on the exterior cladding of the building, or it could be out in the landscape of the property.
You unscrew the lid, if you have a backup, normally the water will be sitting right there when you take the lid off. if there is water there, then that line is definitely clogged. And you can snake it from there.
If you don’t have a clean out, usually it’s an additional $300 to pull/remove the toilet, put it to the side, then you have to run the snake line from there.
When we pull the toilet, we always put a new wax ring on to seal it properly, then put the toilet back. R&R the toilet.