take everything out the car, all plastic to be painted, remove any switches or buttons to be unpainted where possinble, mask off the rest, get a heater in your shed (or painting area), cover anything around that area in blankets, especially mechanical parts, bikes, tools etc
get all your paint, face masks and goggles, wear a hat if you dont want it in your hair, air born paint gets in everything, and remember to keep the door or a window slightly ajar to keep a supply air coming in, but not so that the draft blows the paint everywhere
built up fumes could knock you out cold as they are toxic
read some online advice about spray painting to get a solid idea of what to do, techniques and hints, tricks etc
such as when you stop spraying, tip the can upside down and spray off until it stops, theis gets the paint out of the nozzle to stop blockages
shake very well for 30 seconds or so before starting, or the paint can come thin and thick or block in the nozzle etc
day 1, remove all parts, mask bits off etc, and clean everything with white spirit and a rag, before cleaning with white spirit you can rough the surface up a little with some wet and dry 400 grit, be gentle with it though, you only need to lightly score the interior parts to get a good paint adhesion, so then apply base layer plastic primer to clean surface, cover all visable surfaces and edges (mask off any switches/ buttons etc with lots of cut to size paper tape), leave with heater on to stand for a few hours
day 2, get your first colour coat on it, light airy layers holding can 6 to 8 inches from surface in smooth movements in same direction horizontally every time!!! you must be patient and take ages to do it, or it will run badly and ruin the whole thing, sending you back to square one, remember to empty the nozzle as above each time you stop painting to move parts etc
for parts which you would need to finger surface areas, find some string and hang them from the roof or a high shelf etc so you dont have to finger the wet paint
ideally set up a small heater with a fan blower in it, in your shed to keep the paint warm and dry, damp cold air takes much longer to harden the paint
once you have got a thin first colour layer on, leave it to dry for most of the day with the door shut and the heater on, come back a few hours later (give an hour longer than the tin says!), and add your 2nd layer, in the same way, nice and thin, airy strokes across about 8 inches from surface, it will be looking much more solid now nice and thick coated
leave overnight to harden with the heater on for a few more hours as before, dont leave the heater on over night though, just incase
3rd day, apply a thin clear lacquer, you only need one coat but if you use 2 you get a fine glossy finish which can be polished in future when valeting your car etc, apply lacquer same as paint and give a little longer to dry with the heater on
1x 300ml plastic primer grey or black (usually only in 300ml cans)
2x 150ml cans of the colour you want (various finishes of black available) 1x 150ml clear lacquer
you wont need all the paint in the 2 colour cans, but always have 2 so you can get the colour coat exactly right, uneven coats are obvious on the dash and look bad, if one can blocks then at least you have got a spare
i recently painted my bumpers over a weekend in this way, interior will be the same
if painting this in the car cover everything with plastic and tons of tape and make sure you cover absolutely everything, air born paint lies in waves that you wont see at first and will blow around all over the place if painting outside and not in a garage
i would strongly recommend you take out all plastic parts to be painted and do them in a shed or somewhere out the way, you will get a much better finish if you can get right into all the nooks and crannies
ps, for a misty matt finish, dont use lacquer, use matt, or satin black colour paint in 2 or 3 coats, this keeps the smooth misty effect without adding any gloss
there are paints available now, with cracked stone, marble, leather, and wood effects, and even chromed paint in almost any colour, just hunt around