First prepare the materials. You'll need pins
Once the materials are ready, select a part where want to insert the pin. Now mark that spot with a pencil/pen and then right after start drilling it with the pin vise. Make sure that you drill straight so that the pin wont curve when you insert it.
After drilling, wipe out the excess plastic from the hole. Start preparing the super glue by putting it on top of a wax paper cut out. The glue wont dry fast with this method allowing you ample to have time to apply the glue on the hole. Use a toothpick when applying. After this insert the pin and let it stick on the part. Remove the excess pin with the pliers and that's it! You've now added a pin to your gunpla!
It will look something like this:
Be sure to try this trick to enhance the looks of your build!