Practice:

There are some very good practice tracks for sale. You can go to this link and buy just one copy of the recording of your voice part for about $7.00. Scroll down a bit and select your voice part where it says “Rehearsal track options” (just above the button for adding to your cart).

If you listen to video on Youtube, be sure you are listening to the SATB arrangement, not the 3-part arrangement. It can be difficult to tell which one is presented.