Its best to start with young females. Set up the 30 gal tank with plenty of hides (toilet paper tubes, paper cups, etc) a couple food dishes and two or three sipper bottles for water. Put the male into the cage and then all the females (as quickly as you can without dumping the lot in at once LOL).
As everybody is in new territory, all are on equal basis. There may be some squeaking and minor fights as they all get used to eachother As long as there is no blood or nobody look overly picked on (especially the male), you can leave them alone. In a few hours things should settle down. The male will do his best to service all the females (if they don't all come into heat at the same time, he should have no problems doing his duty).
For a breeding colony, best to feed a high protien (20% or more) diet with a fairly high fat content (at least 8% but not more than 14%). You can use dog food as long as it doesn't contain any red dye. (won't harm the mice but can harm reptiles they are fed to). Wild birdseed mix can be used in addition to the dog food. (just buy 10bl bag or more, only costs about $5 or so). Other food you can buy are specially formulated lab blocks like those made by Mazuri. More information about food, setup etc can be found by scrolling down and reading older posts.
What is meant by a grow out tank is once the baby mice are weaned (about 4-5 weeks of age) you can put them into the smaller tank (or just a rubbermaid container) to grow to adult size. This is good to do if you need adult sized mice to feed to reptiles.