Announce 1-68 on Sunday before "Selection Sunday" (i.e. March 8th).
Rank teams 1-68.
Then, any team that wins conference tourney that isn't on the list, replaces teams on the list, starting at the bottom.
Example given in article
61. Illinois
62. TCU
63. Colorado State (replaced by Manhattan)
64. Louisiana Tech (replaced by Northeastern)
65. Tulsa (replaced by Wofford)
66. Illinois State (replaced by North Florida)
67. South Carolina (replaced by Coastal Carolina)
68. George Washington (replaced by Belmont)
Link
Rank teams 1-68.
Then, any team that wins conference tourney that isn't on the list, replaces teams on the list, starting at the bottom.
Example given in article
61. Illinois
62. TCU
63. Colorado State (replaced by Manhattan)
64. Louisiana Tech (replaced by Northeastern)
65. Tulsa (replaced by Wofford)
66. Illinois State (replaced by North Florida)
67. South Carolina (replaced by Coastal Carolina)
68. George Washington (replaced by Belmont)
Link