Hi, I’m making a Voltimeter - Amperimeter for school. Everything is good but the photo our professors sent us has an LM358 with 5 pins, and the LM358 I found in KiCad only has 3 pins. I tried to look in google and realized there are units for the symbols, there is actually 1 unit with the 2 pins I need, but it’s just that so it’s kinda useless.
What can I do? I don’t know if combining two symbols with different units will work.
Please help me.
Well first of all it is easy to make symbols using the symbol editor. You would put the edited symbol in your own personal library. (The standard library is blocked from edits, because those symbols are likely to be overwritten when you update KiCad.)
It looks like you are trying to add power pins to one of the units of a dual op amp. I usually use it that way but often it seems that others prefer a separate “unit” for power so that a dual op amp would have a total of 3 “units”.
But I can try to make it easy for you this time around. Find my libraries posted here:
and in there is my LM358 symbol.
And…the KiCad symbols you refer to are not useless. Rather the choice of whether to have a separate unit for power is more a matter of personal preference. Sort of like box resistors versus zig zag resistors. But I do think that the zig zag resistors provide better cooling. 
An alternative which is less daunting for a new user is:
Select the LM358 from the Amplifier_Operational library and left click three times. Each click will place a different part… see top line… part a & b & c.
Then move part C onto either part A or B, depending on which Opamp you decide to use.
See second line… B& C are merged.
You will probably need to “Hide” the Ref & Value of C to make the component more easily read, as I, and your professor, have done.
Most multi-unit packages are listed this way in Kicad. eg. an LM324 has 4 opamps but 5 symbol parts.
Note: As BobZ mentions, you will need to learn to make your own libraries, symbols and footprints if you wish to design.
EDIT:
U?C is deliberately made with pin lengths and orientation to match exactly with both the opamp symbols AND the 50mil grid. They are meant to be combined. You place U?C on either U?A or U?B… the choice is yours.
Alternatively, as @Piotr says, some people, to aid clarity, prefer to keep power pins, and consequently connecting wires, separate from the main circuit. In that case, if you used several LM358s, you would place all the “C” parts together and out of the way of the main part of the schematic.
And add parasitic inductance
To let you understand that fully (I hope).
KiCad has nothing against if someone would like to define separate symbol for even each pin of OpAmp provided it (KiCad) knows they all are parts of one physical element (footprint). That way you would be able to place each pin at any position at schematic you like.
Of course no one does it as such schematic is harder to understand.
LM358 really has inside two OpAms with common for them both supply pins.
Classic (for me) way to represent it is to have at schematic one OpAmp symbol with power pins and one without. But some people like to have all power circuits in one schematic corner so they prefer to have two OpAmp symbols without power pins and separate symbol containing only supply pins.
The universal way of defining library for it is to make such IC as 3 symbols but power symbol made such that you can place it exactly over one of OpAms symbol adding to it power pins. I don’t know if there is OpAmp symbol in KiCad library defined that way.
For my classic way (not in KiCad) I used so called DeMorgan symbol representation - each symbol can have second representation - for example two diodes in serie in one SOT23 package you sometimes would like to have at schematic in serie or sometimes as semi paralel. My default OpAmp symbol had 3 pins and its DeMorgan had 5 pins. When I placed 2 OpAms at schematic they both had 3 pins and I could change in one of then the DeMorgan flag so changing it to 5 pins.
I hope I explained it clearly.
One more thing. Even you use only one of OpAms in LM358 package you should have them both at schematic to define what you are doing with unused pins.
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