ScratchJR Interface: https://www.scratchjr.org/learn/interface
ScratchJR Paint Editor Guide: https://www.scratchjr.org/learn/paint
ScratchJR Block Descriptions: https://www.scratchjr.org/learn/blocks
These ScratchJR Tips & Hints videos can give you all you need to get started with ScratchJR: https://www.scratchjr.org/learn/tips