There are two possible answers for this question. However, the option "By using the mapping mode to obtain a magnetic bearing from the aircraft to suitable echoes on the display" has been confirmed by feedback to be correct in official exams.

The pilot may take a relative bearing from an AWR display and would then use the aircraft heading to turn the relative heading into a magnetic or true bearing to. Thereafter, the reciprocal from the ground feature can be back-plotted as true or magnetic.

On the other hand, putting the AWR into "mapping" mode allows the radar to reflect off surface features, which can give quite a good indication of the ground profile nearby. For instance, ground mapping radar can allow pilots to distinguish coastlines quite easily, as well as mountain ranges and sometimes even cities.

To establish a fix, the pilots would place the AWR in mapping mode and/or tilt the radar down a lot, then look for echoes on the display that show these features, comparing that with a chart to get an idea of their position. It is certainly a skill, and not one that will be passed through the generations of pilots very well in the modern era, as it is almost useless these days.

Note: There are a couple of other options that are close to being correct, whilst none of the others are completely true. Please send us any further exam feedback you have so we can verify this question and correct answer, thanks!