Ah, the tutorial would have been written prior to MSFS supporting TACANs, so it looks like there are still some references to the old methods in there. We'll get that logged on our internal trackers as something to update.
Wallasey (WAL) is actually a VOR, so it would be tuned into the ILS radio using the 114.10 frequency. The ILS mode would then need to be rotated to VOR, and the ILS/TACAN button would need to be toggled so that ILS is displayed.
If you wanted to use a TACAN instead of the WAL VOR, you could use the Warton (WTN) TACAN. That can be entered into the TACAN radio as 79X, and has a range of approximately 60nm. It is located 23nm northeast of the WAL VOR, so it could be used as a replacement Navaid on the tutorial flight.
Hope that helps, and apologies for the confusion.
Mark - Just Flight