I've been in your shoes as a contract-temp-worker and too was blamed for mistakes that could have been avoided, had I been trained properly before the employee quit her position that I filled in for only 6 months.

I showed the supervisor the horrible instructions left behind by her employee, and was told that I had to figure out the "gaps" in the processes myself. It took me the entire 6 months to get the job's processes correct, and I wasn't hired on long-term when my contract-temp assignment ended.

When there's bad blood between the boss and their employee, and the new employee comes in, the situation is precarious for them. My suggestion; make friends with other people in your department so that you can ask them questions about your role. Also, you'll have to stay late or come in early to get ahead in your job's learning curve, if that makes sense?

At this point, I wouldn't wait for any further instruction offered by your boss. I would turn it down any help from your boss since he/she has given you bad instruction already on how to do your job.

This is a sink or swim situation and your best choice is to just buckle down and figure out the job, ask your colleagues for help if they are free and know how to help you, and give yourself some credit for doing the best that you can in a bad situation.