Rectilinear Figures

[independence]

I'm aiming to study a topic called Locus (Loci). But someone told me to study coordinate geometry and rectilinear figures first before getting into Locus. Where can I study both of these topics? Especially that rectilinear figures I couldn't find a relatively clear explanations on any website...

 

[Denis]

Were you not told what the "pre requisites" of this course were?