Yes I have noticed a large number of illiquid securities on the TT platform. It's ridiculous that there are so many contracts people don't trade, makes it harder for those of us who do want to trade them. Anyhow, I was just testing out the platform and trying random limit order prices. Of course they need to be matched to be filled in reality. Seems a good platform overall.Oh that’s not a good assumption. By using the web version on a much larger screen you will be able to pull up many more windows simultaneously and you will be able to get a much better feeling for the functionality.
But the first thing you need to do is to learn what the different order types are and how they work. Entering a limit order 500% away from the currently traded price is pointless.
TT is the best futures trading platform there is IMO. But you should know that SIM demo trading environments are not realistic and there are usually P&L errors. Lots of threads here on ET about this over the years.
Finally, you are using mostly dated expiries that are illiquid. It's not reasonable for you to assume that a SIM environment will be accurate for those dated expiries.