If you want to establish residency for tuition and fee purposes, you would have to live in Iowa for 12 consecutive months. During those 12 months, you could be registered no more than half-time at any institution in the state. For an undergraduate student, this would be no more than six semester hours during the Fall semester, six semester hours during the Spring semester, and no more than four semester hours total during the Summer sessions. For a graduate student, this means enrollment not exceeding 5-5-4 semester hours. This enrollment maximum is cumulative enrollment in Iowa. It includes your UNI courses, Guided Independent Study courses, community college courses, classes at all public and private Iowa colleges, etc.
In addition, you could not be claimed as a dependent on income tax returns in another state. When you are living and working in Iowa to support yourself, you need to file Iowa resident income tax returns.
We also expect to see that shortly after your arrival, you did things to establish an Iowa domicile. Usually this means obtaining an Iowa drivers license, registering any vehicles you own in Iowa, and registering to vote in Iowa.