On each day of the Bench Basho, you will be matched against another Bench rikishi. At the start of the basho, you will be scheduled against Bench rikishi with a similar rank to you. As the basho progresses, you may (or not - it is not always possible to do so!) be matched against Bench rikishi with a similar record to you.
Those Bench rikishi ranked in Sanyaku and the top Maegashira ranks will, normally all face-off against each other during the basho. On the last day, the last three matches will normally feature the two topped ranked bench rikishi against each other, the 3rd and 4th ranked, and the 5th and 6th ranked, regardless of their records to that point.
In short, the Bench sumo Torikumi will reflect as close as possible the Torikumi used in real sumo.
The Torikumi gyoji/shimpan will endeavour to send out each day's bench torikumi two days in advance, and before the equivalent real Torikumi is announced.