Shalom! When it comes to understanding the rules of building the sukkah it can get a little complicated,

Sukkah Walls:

 1) Amount of walls

It is advisable to make four sturdy walls. However in the event one will not have four full walls, Three walls still qualifies for a kosher sukkah.

2) Wall material

The walls may be of any material but must be sturdy enough to withstand an ordinary wind.

3) Specific Materials

If one uses cloth for the walls, it must be tied down securely so that it does not flap in the wind; otherwise the sukkah does not qualify for a kosher sukkah.

4) Height

The minimum height of the walls must be forty inches (ten tefachim).

5) Width:

The area enclosed by the walls must be at least 28 inches wide and 28 inches long (7 tefachim)

If the sukkah is narrower than this minimum it is not qualified for the mitzvah 

(even if the total area is equal to or greater than 28x28 inches.)

S'chach - Sukkah Roof:

1) General

The covering of the succah, or as it is more commonly known, the s'chach, must be composed of materials which:

a) grew from the earth,
b) have been detached from the earth,
c) are not susceptible to tumah [contamination].

Thus metals and leather, growing trees, and foodstuffs, are excluded respectively for the above three reasons.

2) Boards & Beams

Boards or beams measuring more than 16 inches in width (four tefachim) may not be used even if they are stood on edge, because such wide boards are similar to the roof of a house.

3) Ratio

The s'chach must be spread over the succah so that it covers most of the open space and the "shade is greater than the sun'

4) Stars Visibility
The s'chach should be porous enough to enable one to see the stars at night but it is sufficient if the stars can be sighted from even one spot in the sukkah,

Moreover in general one may assume that stars can be sighted even when the s'chach is thick,

for it is virtually impossible for s'chach not to have some openings.

5) Quality of S'chach

One should not use s'chach materials that emit an unpleasant odor or whose leaves drop off continually.

Decoration:

1) General Decoration

Even if succah decorations are made from materials not qualified to be s'chach, they do not disqualify the succah, provided they are hung within 16 inches (four tefachim) of the s'chach.

2) Lighting fixtures

Lighting fixtures are treated as decorations. However, if suspending them within 16 inches (four tefachim) of the s'chach will create a fire hazard, they may and should be suspended more than 16 inches (four tefachim) below the s'chach.

Where & When:

1) Location

A succah may not be erected under a tree or the overhang of a house. If a branch covers part of a sukkah a competent authority should be consulted since the subject is complex.

1) When

One should begin to build the succah, if possible, The night of Wednesday, October 5, 2022 on Motza' ei Yom Kippur (the evening following Yom Kippur). in order to go from one mitzvah to the next, and complete its construction on the next day.