Hi Sadiq, as mentioned in the starting tips thread
when asking a question of this type it's a good idea to tell us your palette. So if you have any similar mixing questions in future please list which paints you have available.
None of the paint names you mention would be just a single colour so please note that any suggestions will only be approximate and may not match what you're looking for. Starting with Indigo, this is a very blackish blue and something of the right sort can be mixed fairly easily; if you have Prussian Blue that mixed with any black would work. Alternatively, French Ultramarine plus some Burnt Umber or Phthalo Blue plus Venetian Red are other options.
Naples Yellow paints vary a great deal, from dull orange-yellow to a light yellow in colour; some indication of the variety is shown by the picture in this thread
. The duller orange type is probably best made starting with Yellow Ochre or a similar yellow earth with a little red or red earth, possibly with a little added white; the yellower types from a mix of white and yellow or white and Yellow Ochre, with a dot of black for some versions. Sometimes Naples Yellow Light paints are just the Naples Yellow from the same range with some white added.
Olive Green is a very vague colour concept so any of these might give you the right sort of colour: Yellow Ochre + black; Yellow Ochre + Prussian Blue; Cadmium Yellow + Black; Cadmium Yellow + French Ultramarine.
Something to bear in mind is that each paint in your palette is not an end in itself, what matters really is the colours you mix from
them. So none of these colours should be thought of as essential or necessary.