Hi and welcome
For a first carving , I am impressed with 2 things , first that you finished it and second that you came here to ask for some help on staining.
I like the choices you made with the paint, to do a seperation of the landscape, this really helps is seeing what you wish to acheive.
I will answer your question first, chances are he used a pre-stain. this is a wood conditioner that is use on wood to allow the stain to be consistant in coloration once applied. Many woods will react differently in places to staining , so if your do not use a pre-stain you can eaisly end up with light and dark sections in your stain.
Lets say you chose to use a cherry stain, without the conditioner you will have a color that will be everything from a light pink to a almost black red inches apart. giving a very poor appearence to the wood. This is especially true of some of the basswoods, the pre stain will just even this out.
Now for some basic instruction I strongly suggest you go to Susan Irish's sight and read the landscape section on her site , great information and an excellent place to see step by step help the address is
www.carvingpatterns.com.
Welcome to carving and look forward to seeing more .
Ash