Can someone help me? I got some help from a friend but I still don’t get it

STEP - BY - STEP EXPLANATION
What to find?
• Surface area of the cylinder.
,• Volume of the cylinder.
Given:
Radius = 3.5
Height =14
π is a constant = 3.14
The surface area can be determined using the formula below:
[tex]Surface\text{ area}=2\pi rh+2\pi r^2[/tex]Substitute the values into the formula and simplify.
[tex]Surface\text{ area}=2(3.14)(3.5)(14)+2(3.14)(3.5)^2[/tex][tex]=307.72+76.93[/tex][tex]\approx384.7[/tex]Hence, the surface area is 384.7 ft²
The volume of the cylinder can be obtained using the formula below:
[tex]Volume=\pi r^2h[/tex]Substitute the values into the formula and simplify.
[tex]Volume=3.14\times(3.5)^2\times14[/tex]Simplify the above.
[tex]Volume\approx538.5ft^3[/tex]ANSWER
• Surface area = 384.7 ft²
• Volume = 538.5 ft,³