Traps work in this way.
Trap Inside - Directs opposition teams players to the inside once they have passed the midfield. In that area ideally you want roles that will try and win the ball back.
Example formations that work well with trap inside - 5221. Here the DMs are the ones to take advantage. Once you win the ball, counter attacks are released in that direction ie. inside.
Trap Outside - If you are playing a 442 a trap outside would direct players to go down the flanks. Now this means that the opposition once passing midfield would continue to be encouraged down the flanks.
Why would teams use traps.
Trap Inside - Perhaps their wingers are very good at crossing and they have strong target men and you don't want to deal with crosses.
Alternatively you could have very good DMs who are great at winning the ball and are playing static roles.
Trap Outside - This encourages a team that might have very good inside forwards to stay away from driving at central areas, but, this can also be dangerous cos if the team can get to the byline and do a low cross you could leave yourself more vulnerable.
For example, the trap inside instruction was tested with Everton using a low block 5221 and simulated them in a season where they avoided relegation, ended up in Europe and beat Liverpool in the FA Cup final.
This YouTube video is looking at the Pressing Trap instruction in Football Manager 24 breaking down plays using Trap Inside and Trap Outside.
Source: sigames.com