There are different options on how to assign a footprint to a symbol.
Option 1: Via a tool called cvpcb.
Found in eeschema: Tools->assign footprints to components (Might be called differently in your version of kicad.)
This tool allows you to edit the footprint field of all your components in a tabular form.
If you want to assing a footprint to a component, select this component in the middle column and click on the desired footprint in the right column. What is shown in the right column is determined by the filter settings.
Option 2: Via the footprint browser (edit symbol direclty.)
For this workflow simply hover your mouse above the symbol you want to assing a footprint and press e.
In the dialog that opens select the footprint field and either type in the correct footprint by hand or use the footprint browser to assign your footprint.
In the footprint browser you need to select the footprint lib in the leftmost column and the footprint in the middle column. (Single clicking updates the preview, double clicking assigns the footprint.)
Option 3: In KiCad v5 (or nightly), directly in the component selector.
KiCad v5 has an experimental feature to allow footprint preview and selection when browsing symbols. It must be enabled:
- Open Preferences → General Options.
- On the Display tab, enable "Footprint previews in symbol chooser (experimental)".
The feature should be considered in "beta", as performance is a bit poor and a few features are still missing, but what is there should work.
In this selection dialog the following options are available:
- By default the footprint set in the symbols footprint field is selected.
- The option "Other..." opens the footprint browser.
- In addition to the default footprint, all footprints that result from the footprint filter defined in the symbol are shown as well.
Setting the default footprint for symbols. (Library editor)
You can setup your lib such that your symbols have their footprint pre assigned. This is called a fully defined symbol. (This footprint will be automatically assigned in KiCad v4. In KiCad v5 you can change the assignment using the new symbol selector dialog.)
Setting footprint filters for symbols. (Library editor)
The footprint filters are used in CvPcb if you set the filter that way. (see above)
They are also used in the KiCad v5 symbol selector dialog to show alternative footprints.
Footprint filters can include wildcards:
- ?: Exactly 1 character (1)
- *: Any number of characters (0..n)