How do I change the key of the arrangement to my voice range?
There are numerous notation softwares that will open the score PDF and change key.
What is the best way to position the instrumentalists during my performance.
Most congregations have a fixed position for the piano. When facing the stage and if possible place the cello(s) on the right, viola(s) in the middle-right, flute in the middle-left, and the violin(s) on the left all behind the vocalist..
How do I play the Accompaniment track during my performance.
One good way is to load the MP3 accompaniment track to your smart phone.
Place two small portable speakers (BOSE Soundlink Revolve Bluetooth work well) on each side of the vocal microphone and connect via bluetooth to your smart phone. Adjust the volume of the speakers just as if there was an orchestra behind you.