Before adding custom aspects through Class Charts, ensure that you have set up the aspects correctly in SIMS.
Log into Class Charts and go to School Settings:
Then click on Custom Fields > Setup Custom Fields:
Click 'Add from SIMS':
In the popup box tick the aspects you want available for teachers:
The aspects can now be available in the list of custom fields and teachers will be able to choose these or the admin can select them for fieldsets or force across the whole school as default.