TrekBuddy will follow a track created from a mapping program, BikeHike or Google for instance, or a track that it has recorded itself. This is stored in the directory called 'Tracks' accessed by pressing '1'. Select 'Tracks' and then your preferred track. TrekBuddy name its tracks in a date/time format.
Selecting the track causes it to be loaded and a list of waypoints are displayed. Pressing enter displays the details of the selected waypoint. Menu brings up the navigation options. 'GoTo' will take the map straight to the start of the track - a usful way of checking accuracy without the GPS needing to be locked.
'Route Along' will display the track as a red line and there will be a green pointer on the rose indication direction to next waypoint. The display may not show the start of the route unless the GPS is locked.
I wouls have POI turned off in 'Settings' 'Navigation' as they are too intrusive.
I use TrekBuddy Atlas Creator now called Mobile Atlas Creator to create maps and find that OS Maps do not work well with TrekBuddy due to the range of colours on an OS Map. OSM display very clearly tho'.
As for battery life the BB lasts about 2-3 hours with the display on permanently (button 3) but I have bought a LI-ion battery pack from portable power supplies.co.uk which extends the life by 3-4 times.
http://www.portablepowersupplies.co.uk/usbliionbatterypack.htm