Hello again!. Let´s start painting this one.
Step 1: Primer
1.- With warm water and soap, clean all the model with care as we have to remove traces of grease (from our fingers), pizza, ice cream and any kind of dirt.
2.- On metal parts, I use Gunze Sangyo´s Metal primer applied with a brush. Yes, with a brush and care. 
With this primer, no peeling risk (my first experience was with some metal schurzen one year ago ... since that moment, I use the metal primer 
)
3.- Once dry, I apply Tamiya´s primer with my airbrush (I do not recomend to spray directly from the can). Do it little by little, in several thin coats until all the model is covered.
4.- Once the primer is dry (24 hours minimum), with a very very very very fine sandpaper, I start to polish all the surfaces to avoid granulated zones and imperfections. It´s the perfect moment to see how strong your PE parts are (and it´s the lunch time to our particular monster in the carpet 
...)
The result:
Next step: Dark yellow base color.
Thanks for looking!