First you need to create a FUT Club.
If you've never done this before, then from the FIFA 16 "Main Menu" use
to move over to the "Play" tab. Highlight the "Ultimate Team" tile and press the
button and begin the FIFA Ultimate Team mode setup.
Now from the FUT main menu, use use
to move to the "Single Player" tab. The bottom right tile should say "TEAM OF THE WEEK" (you might have to
the tile to navigate to it). Highlight this tile & press
to enter this mode.
(You can often find this mode from the "FUT Central" bottom right tab as an alternative method for navigating to the proper tile.)
You can change the challenge if you wish (press
to do this) - as any challenge will net you the achievement. Press the start button
to begin the challenge. Select your difficulty, and press
a few times to get the match to start. (You might want to pause on the the kits screen as the default for the TOTW team is white - and it will suck - a lot - if your kit is also white. You can change the TOTW to black if necessary.)
My suggestion is to do this on Beginner or Amateur difficulty - and win the match - just to be sure you net the achievement - but I'm fairly certain you just have to compete the match, and not necessarily win it, to get the achievement.
Overall it's another easy achievement.