What a nice little machine, I did not know they produced one like that. You will benefit from proper mic preamps which the Zoom products I use (for broadcast sometimes) lack.
It is a professional machine and I assume suitably priced too so I don't expect it to be hard to get a result from it but it may need tweeking to get the best from it.
What in particular do you need help with? There will be options regarding mic gain, bit depth and compression, where do you stand with those aspects? Being a Nagra, it will be pretty robust and you will not be able to break it so it is best to have a play and if you like what you hear you are more than half way there.
If there is a link to a free copy of the manual, please supply it and we can go from there. One further thing, you will need high quality mics for your birdy activities, low noise and highly directional mics of a professional standard will make all the difference. For recording lectures, any decent cardioid will do.
Off now to check the price, I have a weakness for these card recorders!