How to properly connect the candlestick connector to the electrical installation

A candlestick switch again, I hope the last one.
Here is a playlist with electrical systems using a candlestick connector:
How does the candlestick switch work? - double connector Vteka • Jak działa łącznik po...
• Podłączenie lampy sufi... Connecting a ceiling lamp to a double switch - step by step | Vteka
• Jak podłączyć🔌 żyrando... How to connect a chandelier for 3 light bulbs- change from one to two circuits | Vteka
• Przyłączenie i montaż ... Connecting and assembling a chandelier Vteka
• Podłączenie żyrandola ... Connecting the chandelier via a double switch (candlestick), variant No. 1
• Przyłączenie żyrandola... Connecting the chandelier via a double switch (candlestick), variant No. 2
• Jak podłączyć żyrandol... Smart home. How to connect a chandelier? ZAMEL SUPLA ROW-02 | Vteka
A distinction is made between wire markings:
• one color for cables that do not function as a protective conductor,
• two-colored for wires with various protective functions.
It allows marking wires with the following colors: black, brown, red, orange, yellow, green, blue, purple, gray, white, pink, turquoise.
Color markings should be used at the ends of the conductors, preferably along the entire length of the conductor.
Insulated wires should be marked with a color by using insulation of the appropriate color or / and by means of colored markers.
The bare wires should be marked with the appropriate colors at the end and at the connection point.