Maybe this will be helpful? https://na.finalfantasyxiv.com/jobguide/battle/
It shows you the basic rotation there. For example, here's a screenshot from the samurai guide.
https://i.imgur.com/k7rrMBw.png
edit: here's the machinist basic combo (obviously there's situational skills and other attack buttons but you said you're fine with situational skills)
https://i.imgur.com/VwfNX2M.png
