A rough time guide for each study would be to allow about 15 minutes for the Relate section, about 30 minutes for the Respond section and another 15 minutes for the Reflect section. Sometimes you will go longer than that, especially at the end. Reading the passages at home before the study helps you become familiar with the topic and gain more from your group discussion. Any study can be used on its own, so you could select some to suit the number of weeks or studies you want. If your group is large, you will gain more by working in subgroups of about three to five, particularly for the final section of the study.
Smaller groups allow more personal sharing and specific prayer.
The readings include passages from other gospels as well, especially John. These group studies may be used following the lectionary dates or may be used independently, in full or in part, at any time. Appendix 1 gives you an outline of the lectionary year. I at the Lent to Pentecost seasons. So the first study both looks toward the fulfilment of the coming of the Lord as King and introduces the advent of Jesus.