I don't know why they archived it.
For video content, you can look for past sessions of QGSS (Quantum Global Summer School) on YT.
For beginners: https://quantum.country/
For exercises, you can go through past Qiskit Challenges: https://research.ibm.com/projects/quantum-challenges
Eg. https://github.com/qiskit-community/ibm-quantum-challenge-20...