Two ways in
With a class code. Ask the adviser for the 7-character code. Join → pick your subject → the roster is there. This is the best path: nothing to type, and the adviser sees your grades on the report card automatically.
Standalone. Start a gradebook with your own learner list if no adviser is on SchoolAide Lite yet. When the adviser joins and creates the section, you both get a prompt to link. Linking merges only the learner list — every activity and score you encoded stays exactly as it is.
What you can see
Your own subjects. In a section someone else advises, the other subjects, the roster details and the release tools stay with the adviser.