1. Unpack the file you have downloaded from POIplaza.
2. Convert the downloaded .asc file into .dat with POIEdit available at http://www.poiedit.com/index.htm.
3. Copy the selected files (.bmp and converted.ov2 extensions) to the relevant map folder.
4. Launch the TomTom application and select the "Change preferences", followed by "Enable/disable POIs" and select the desired categories.
Note: The POI may be displayed as an inaccessible location if the map you are using is not sufficiently detailed.