Lots of nights and weekends teaching Initial students in the simulator. Occasionally they work some of the holidays. Recommend you read 14 CFR Part 142 to learn the requirements to be an Instructor or Training Center Evaluator (TCE). Also a good read is FSIMS FAA Order 8900.1, Volume 3, Chapter 54.

If hired, you can expect the following:

Complete Initial ground training in Make/Model
Complete Recurrent ground Training in Make Model
Repeat the above until you are comfortable with the material

Practice teaching ground to another experienced instructor
"IOE" observed/proctored "student teaching" real students

Operating a simulator takes some time and practice to learn. Eventually you will be doing both ground and sim.

You will need at least one year as an instructor and 100 hours of simulator instruction time under your belt before you get selected for TCE. Once you are a TCE, you will be doing 61.58 Proficiency Checks
And be observed at least once a year by the Feds. After a year as a 61.58 TCE, you could get additional authorities to issue ATP's and Type Ratings. It is hard work, but very rewarding work for the right person.