user49416: I am new to electronics and am currently working with an Arduino UNO. I know the basics of PCB manufacturing (Besides, I'm fiddling with mine, very basic of course) Anytime I'm curious about how to get from Arduino to a finished PCB with the same result only on my Arduino prototype?
For example, my project has several components such as leds, An RFID module, a TFT LCD Shield 3.5 ", another 240x320 OLED screen ... How to put all this on a printed circuit board?
Do I need to solder the same components to my PCB?
-Do I need to run my Arduino code on my PCB once it is assembled?
-.......................................

user31105: A printed PCB can be used to place your components on (typically resistors, ICs, capacitors etc).
However, if you want to connect an LCD or big components, it would be a waste of space for your PCB. So in that case, I guess the best way is to create an enclosure where your displays fit in (and your RFID module if it is big too), and create some kind of connector from the PCB (e.g. using a terminal block or other way) and connect it to your displays.
On your PCB also an Arduino needs to be added, I guess the best solution is to use the Arduino chip (AtMega328P probably), and some external circuitry needed. Optionally using an IC socket in case you want to change the program later on. 
On some Arduinos you can take out the AtMega328 DIP28 IC from your Arduino Uno board. Program it, than place it in the socket on your PCB board.
Update
Maybe you can use an Arduino Micro or Nano and place that directly onto your PCB (with headers preferably). Than you get something like below:


49416: <p>I am new to electronics and am currently working with an Arduino UNO. I know the basics of PCB manufacturing (Besides, I'm fiddling with mine, very basic of course) Anytime I'm curious about how to get from Arduino to a finished PCB with the same result only on my Arduino prototype?</p>

<p>For example, my project has several components such as leds, An RFID module, a TFT LCD Shield 3.5 ", another 240x320 OLED screen ... How to put all this on a printed circuit board?</p>

<p>Do I need to solder the same components to my PCB?
-Do I need to run my Arduino code on my PCB once it is assembled?
-.......................................</p>
 31105: <p>A printed PCB can be used to place your components on (typically resistors, ICs, capacitors etc).</p>

<p>However, if you want to connect an LCD or big components, it would be a waste of space for your PCB. So in that case, I guess the best way is to create an enclosure where your displays fit in (and your RFID module if it is big too), and create some kind of connector from the PCB (e.g. using a terminal block or other way) and connect it to your displays.</p>

<p>On your PCB also an Arduino needs to be added, I guess the best solution is to use the Arduino chip (AtMega328P probably), and some external circuitry needed. Optionally using an IC socket in case you want to change the program later on. </p>

<p>On some Arduinos you can take out the AtMega328 DIP28 IC from your Arduino Uno board. Program it, than place it in the socket on your PCB board.</p>

<p><strong>Update</strong></p>

<p>Maybe you can use an Arduino Micro or Nano and place that directly onto your PCB (with headers preferably). Than you get something like below:</p>

<p><a href="https://i.stack.imgur.com/0doIf.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0doIf.jpg" alt="enter image description here"></a></p>
