Yes you appear to be getting the hang of it very nicely.
so
y=7 sin3x -6
1) midline dashed line
2)topline (my term, not formal) very light line
3) bottom line (my term, not formal) very light line
4) wavelength
5) A quarter of the wavelength (this will help with choosing the scale on the x axis)
6) What would be sensible points for the x axis?
7) Will it start on the midline, above or under, why?
8) Will is start going down or going up, why?
9) y intercept
10) plot 4 (or 5) points in advance just by knowing what the properties of the graph will be.
(I mean maxima, minima, and points on the midline)
11) Graph it from x=0 to x= wavelength
12) what is the first maxima? (read from graph)
13) what is the first minima?
14) What points are on the midline?
Copy all these questions and answer on your own post. You can check your sketch and answers with Desmos.