There are three different methods for changing your tactics this year. The first is the quick tactics bar, which is visible on the pitch at all times and can be moved around to wherever you want it. From here, you can make a quick sub, change formation, quickly change mentality or team shape, give team instructions, or give a touchline shout.
The second method is by clicking on the tactics tab. This has two tabs itself, either pitch or list, and whichever one you used last will be the one it defaults to. From either view here you can make subs, change the player’s roles, and from the pitch view you can also move around the formation. Also on this view, the right hand side contains links to Tactics, Team Instructions, Set Piece Takers, and Opposition Instructions which will open up those panels in a new dialog.
This dialog is the third and most advanced way of changing tactics, as it incorporates the full tactics panel used outside the match and has tabs for every other area of tactics you may wish to change.