Original: The law required states with land-grant colleges (such as Oklahoma State University, then Oklahoma A&M) to either admit African-Americans, or provide an alternative school for them to attend as a condition of receiving federal funds.
Simplified: The law made states with land grant colleges (such as Oklahoma State University, then Oklahoma A&M) to either allow African-Americans in as students, or provide an alternative school for them to attend. This was required in order to receive federal money.