Anyone got tips or tricks for Raid: Shadow Legends?

I'm level 18 after a day and the offer is giving 13.9k SB.

https://preview.redd.it/dlq2kzamum7b1.png?width=1196&format=png&auto=webp&v=enabled&s=f4cc76a8dcb0b0d2108c7a21c2a0af95b608d3d3