The format is what CAF used for 2014. 26 teams start in Round 2, and 28 teams start in Round 1. https://en.wikipedia.org/wiki/2022_FIFA_World_Cup_qualification_(CAF)#Matches has the Round 1 matches, which will be from 2 to 10 September. The 14 aggregate winners and the top 26 teams will be drawn into 10 groups of 4. The group winners will play aggregates to determine the 5 qualifiers. October and November have Africa Cup of Nations qualifying, and the WCQ Group Stage starts in March. http://www.football-rankings.info/2019/08/caf-qualification-world-cup-2022.html has Round 1 probabilities: Zimbabwe* 93.11% vs. Somalia Eswatini* 82.40% vs. Djibouti Equatorial Guinea* 75.58% vs. South Sudan Rwanda* 74.41% vs. Seychelles Namibia* 71.44% vs. Eritrea Togo* 71.12% vs. Comoros Guinea-Bissau *66.47% vs. Sao Tome e Principe Mozambique* 64.76% vs. Mauritius Chad 58.90% vs. Sudan* Gambia: 55.80% vs. Angola* Botswana 54.65% vs. Malawi* Liberia 53.21% vs. Sierra Leone* Burundi 52.78% vs. Tanzania* Ethiopia 51.71% vs. Lesotho* I wrote that with the higher probability first, not to show who hosts what leg. The teams with the better FIFA Ranking are marked with a *, and those teams host the second leg. The formula expects the team with the better FIFA Ranking to advance in the first eight pairings and the team with the worse FIFA Ranking to advance in the last six pairings. By "first eight" and "last six," I mean the order I typed them in here. The pairings are not in any order related to qualification.