As the professor, you are one of the biggest influences on whether students will take full advantage of SI support in your class. We encourage you to collaborate with your SI Leader before/after class or during office hours, and help advertise the SI sessions.
Here are some tips on how you can help advertise SI and promote attendance
First day of class and first session
Introduce the SI Leader to the class, and explain how they stood out in your class
Allow the SI Leader to make a 3-5 speech during the first week of class to introduce themselves and answer questions
Collaborate with the SI Leader
Share resources that the SI Leader can use, and mention concepts they should focus on in the sessions
Help make the first SI session relevant by working collaboratively with the SI Leader to come up with a good beginning of semester activity for the first SI session. If students attend an SI session early on and get a lot out of it, they build community and tend to utilize SI much more often throughout the semester.
Announcements
Insert a blurb about SI in your syllabus
Promote test reviews in SI!!!
Talk up SI during class, making frequent announcements
Encourage the SI Leader to post reminders to students on the board or in the chat during class
Allow SI Leaders to make classroom announcements throughout or pass out fliers promoting the SI sessions throughout the semester
Allow SI Leaders to add announcements on your class Blackboard site, and utilize it to advertise their sessions
Incentivizing (completely up to your discretion!!)
Consider incentivizing SI sessions with extra credit or including it in the course grade
Share a test review and answer keys with SI Leader to cover in sessions
Consider sharing with the SI Leader a previous semester's test with different problems, and the answer key, so it can be used as a test review