The 10 meter band is divided into different sections for modes of operation like many of the Amateur bands.
Typically the bottom portion of the bands are allocated for CW ( morse code) and data. On 10 meters, this is from 28.000 MHz to 28.300 MHz.
SSB is from 28.300 MHz and up to 29.700 MHz. However, above 29 MHz is typically used for FM repeaters and Simplex.
The area where you will find most SSB voice on 10 meters is between 28.350 MHz to 28.600 MHz and using upper side band (USB). A garbled voice that you were referring to may be because you are on AM mode or not on upper side band.
Don't worry about Q codes, Q codes were developed as a short hand method for CW. Although people use sparingly them on amateur bands, they are frowned upon if used excessively. CBers can be notorious for using them as such.
The most common acceptable ones used in moderation on Amateur bands are:
QSL means an acknowledgement, affirmative
QRT means signing off and clearing the frequency on SSB
QST means an announcement of interest
QSO means a communication with another
QRM means interference by another station transmitting near your frequency
QRN means interference from noise or excessive static
QSY means to change to a different frequency
QRZ typically means you are being called by or who is calling me
QRP means a low power transmitter usually 5 watts or less
Your last question on how often to identify with your call sign is every 10 minutes for U.S. stations. Other countries rules on this vary.
You are more than welcome to listen to Amateur bands, but you should consider getting a license if you think it is something you would like to do.
