The "general admission" is in sections E-K in rows 30-42.
They have security standing at Row 30 in every aisle. Starting with row 30, it's all about who gets there first. The seat numbers printed on your ticket don't mean anything.
They don't check your tickets. If you really wanted to, you could sit in rows 1-29 of those sections.
Majority of the students stand, so if you don't want to stand, I would recommend sitting towards the top. If you sit in rows 30-35, you'll likely stand most of the game.
You don't have to arrive early. We arrived with 20 minutes to go before tip off against Iowa State and we sat in row 30 in section E. Even at tip off, there were 4-5 seats together empty all around us. A lot of people that buy the general admission tickets won't even be in the seats. They will stand at midcourt (which provides a good view, too)