How to choose correct orders?

When im playing against different formations i choose different orders for same formation. But the result is not so great. Default orders for 4-5-1v in this forum is def/flanks/mixed/on but it doesn't work for me at all for a long time. Sometimes its even better to play though them middle (against 3-4-3 isn't it ridiculous?). For example against 4-1-2-1-2 narrow it would be wise to play down flanks but assistant usually says that passes are blocked on the flanks. Same with 3 defense formations.
Yes, there is a lot of information about all this on forum but when the new layout came - it's all different now, nothing works the same. That information looks a bit old and dull.
So i am a bit confused

yes, the game (formations and orders) has changed a lot the last months, 1/2 year.
short passing + attack can work also with counters now

Assistant say that because his wing def are intercepting your passes. Means they have good def skills. Before was easier through flanks because most managers were training DL/DR mostly on speed, cross and pass and slightly ignored defense skills.
It's harder to pass a DR/DL with good def skills and good strength.

Hey but i i get it against 3dc formation too. Well i wouldn't say that it is impossible(maybe they are good defenders) but when you go with 4-5-1v against 3-4-3, focus your passing through the middle and assistant says that it was wise to play through the middle than so..... I don't know what to say.
Or for example you play against 4-2-3-1. Play with short passes and high pressing. Its all fine and good(that's how it is interpreted). But you play next match against same opposition and its go all wrong and bad. Total failure.

you 're right.
4-5-1 V should work vs 3 DC but after the update in Team's set up (using boxes, remove arrows), a lot of counter formations have changed.
Now you can see 3 DC moving as winger defenders.
Positions don't matter any more.
Many times orders also don't work.
Better to be present in the game and try to "read" how it is going and do adjustments.

Do you have any tips how to read it? Only one real helper is assistant but he isn't just helpful. For example "You should be concrete in your actions give you nothing and it makes even harder for you to do proper adjustment. Or he says to try to do something to control your midfield and second tip from him is try to play counter attacks. Hm, not logical, is it?

To be honest, it's mostly about looking for patterns in the tactics of your opponents, and not being predictable tactically yourself. Once you become savvy is spotting patterns, you'll develop a pretty good idea of how to setup tactically for most opponents. Against managers that change stuff in match, watch the ratings, animations and match statistics, to try and workout how they've setup and what they've changed (this is difficult to do).

Regarding 4-5-1v defense/flanks/mixed/on. It's a common setup and the dilemma with this game is that the types of systems that work best in the real-life, ultimately are the most predictable tactics in top eleven, so they have a tendency to fail more often than they realistically should. For example, if playing against 4-5-1v and the opponent is in an association that is in the gold leagues or relegation danger in platinum, as a general rule of thumb, probe for a defensive + counters strategy first. Adjust later if needed; more often than not that manager will be playing defense + counters.

I did recently encounter an opponent playing 4-5-1v attack/short/on as the moderator mentioned above. That manager happened to be in the world #91 association when I played him. First leg I beat him 3-2, got spanked in the return leg 0-4 (I was stupid, went down 0-1 and starting changing stuff for no reason and snowball effect instead of staying patient). The more unorthodox setups tend to exist further up the totem pole. It really boils down to, spotting patterns, not being predictable and in-match adjustments.