[Merkaba]

go through all of your vowels. ay, ee, I, ooh, uu, and ahhh do them all at various levels and octaves. keep it in chest or head for a while. it helps warm up the edges of the cords, which is what you use in falsetto. after a few minutes move your way up to falsetto. even if you dont use it, you want to go to falsetto in your warm up. if youre going to be singing professionally. of course dont do anything with alot of push while youre warming up. or at least until youre fully warmed. alot of push is part of my warmup but i do it at the end. and do scales with each vowel, do one or two legato, i think thats what its called, you connect together without a pause in between. then do one or two staccato. which is with a pause in between. then do vowels starting with H's. hay, hee, hah, hi, ho, hu. and do crescendos and decresndos in volume. you can do that with one note. dont get into the habit of automatically crescending in volume when you do a scale going up. many people do and this can lead to breaks and bad notes. and do a gliss on a single note. gliss up and down. varyring the intensity and octave. do some starting low and go as high as you can while remaining relaxed of course, and without straining. then do some going down. oh, a gliss is where you go up or down in pitch, with one smoothe sweep, like half of a siren. And practice it while trying to maintain the same volume. you can also start off by gargling with sound and gargling scales. it reads like a lot but all of this shouldnt take you more than a few minutes. and your warm up should vary in time depending on your current condition, yesterdays work, todays work load and its time. and tomorrow's. warm up longer for a shorter gig and vice versa. if i had a twenty minute gig i would be doing what i consider warming up for an hour. you will have to find out the time you need. you can also sing songs by just using a single vowel. dont do any hard songs of course. be sure to sing from the gut support, and not your throat. and be sure to warm down. do glisses from your highest falsetto down to your lowest chest voice. do each vowel. and then end your vocal day/gig with normal push on eeee'.s do about two minutes worth. low to high, then high to low. always end with high to low glisses. then sing eees at a normal pitch. eees help your cords realign, thus helping them to heal and cut down on protective mucus.
hope this helps. check out some of my other posts around this forum.

and what exactly do you mean, youre going to be backing up or what? and vocal training on your own or with a teacher? nonetheless, nothing worse than a bad vocal regardless of the purpose. so warmup good.