This achievement is achieved on the Manager Career gamemode.
Under the "Office" tab, select calendar and sim to the closest league match (you will not get the option to attend a press conference if it is a friendly)
Once you are at the date of the match select match day. You will be presented with 4 tabs, Complete the Pre-match Report, Training session & Press Conference.
Pre-match report can be opened and closed for it to be completed (see green tick next to Pre-match report tab).
Complete the Training Session by completing any chosen skill game.
Finally enter the Press Conference and complete this.
*Be sure all have green ticks to confirm you have completed each task*
The achievement should now unlock