I’m new to watching football and now genuinely very curious and confused after Spurs vs Chelsea match the offside rule.

Why is Chelsea’s second goal not an offside? It seems to me when Sterling passed the ball to Jackson, Jackson was in an offside position. https://youtu.be/j1-8N0Q5-Uw?si=jOE4Utexk_m0F91X&t=528

The same thing also happened with Chelsea’s third goal. https://youtu.be/j1-8N0Q5-Uw?si=jOE4Utexk_mOF91X&t=600

Am I missing something with this offside rule here?