You can find more details on the Minnesota Budget Project's blog, but the general idea is to replace a variety of tax breaks that are either regressive or too narrowly targeted with three simplifying tax credits, including credits for mortgage interest, charitable contributions, and lower-income families with children. Tax rates on the lower two income tax brackets would also be reduced.
On the business side, the proposal seeks to end a variety of ill-conceived business tax breaks, though unfortunately it does seek to replace them with other ill-advised measures, such as single sales factor and equipment expensing.