At Grade 3 you will be expected to know how to recognise, create and use all tonic triads for the grade i.e. major and minor keys with up to 4 sharps or flats in them.
If you are already happy and familiar with tonic triads then there is no new material to learn for grade 3 – merely the application of your tonic triad knowledge to the new keys for the grade. However, if you require a recap, or are new to tonic triads, then the following videos will help you. The first video explains how to create tonic triads in major keys, whereas the second video tackles minor tonic triads.