Hi...if you have a wooden recorder, it will need a breaking in period. Either way, you can check here to take care of condensation issues:
http://www.lazarsearlymusic.com/Recorde ... r_care.htmFor plastic recorders, I don't tend to have as many problems, but I still have to fling out the moisture (my preferred method...sucking it out makes me gag).
The treble recorder does have the same fingering as the descant, but, it's tuned a fourth lower. The descant (as well as tenor and great bass) are generally "C" recorders, and the tenor (as well as sopranino and contrabass) are "F" recorders. As an aside, there's an in between one that is a treble "G" recorder as well. One think you will want to do is obtain sheet music that is proper for treble recorder in order to be able to play within the correct range. The lowest "C" on the descant is the same as the first 3 fingers held down on the treble recorder (descant "G" position, but treble "C" position). I've had the same problem, playing descant for decades, then picking up treble later in life. I have the advantage of having more musical training in general, but I found the best thing was simply printing up a new fingering chart with the treble fingering and notes, and set that next to any sheet music I'm reading, for reference.
If you are looking to jump into clarinet, remember that they are transposing instruments (concert pitch is not always what is written in the sheet music for the clarinet). My older one is majoring in music, playing clarinet and bass clarinet.
If you want, you can also try out a chalumeau:
https://en.wikipedia.org/wiki/ChalumeauIt basically has recorder fingering, but uses a similar single reed mouthpiece. I will never do clarinet, but I found that the chalumeau serves my purposes (though my clarinet-playing music major daughter looks askance at me when I pull it out).