This video is an example for you can learn:
Placing Orders, Setting Stop losses and Targets, Leverage and Margin
Bitmex Stop Loss Tutorial And Fees Explanation
I am sure there is many more good video for you to watch, you can get something from the video. I hope you can solve the problem, so you don't have a problem to trade in Bitmex.
You give the right advice. Topic starter need to start with their implementation. If this does not help to solve the problem, then he can read reviews on various resources. Reviews, necessarily dedicated to this exchange. As examples: https://www.trustpilot.com/review/bitmex.com or https://revain.org/exchanges/bitmex. If the above does not help, then there is nothing left but to change the exchange.