STATICS

Context:

The structure represented on the figure provided supports a load of $4$kN and possesses two types of support, ball jointed, in D and H$.$

Question $1$a: Determine the intern efforts $($tension or compression$)$ in the AF and AG members using the knots method.

Question $1$b: Determine the intern efforts $($tension or compression$)$ in the BC$,$ BD and DE members using the section methods.

The answers are supposed to be : AF$=5,66$ kN $($t$),$ AG$=4,00$kN $($c$)$

DE$=4$kN $($c$)$ BD$=5,66$kN $($C$)$ and BC $=8$kN $($T$).$

I just don't understand the methodology to get there.

Thank you for your time!