Sample : it's like when you ask for a sample of a food to taste and to check it you like it. Pattern: it's like the design of sth that you can get it through observing. For example geometic patterns in nature and architecture. Template: It is something that predisegned and you work over it. Like a website. You can use a template and you need to build it from beginning.

It depends what context you use them in but generally this is what they mean: Sample = A small piece or part of something that is used to show what the whole piece is like. For example, if you wrote an essay you could read out a 'sample' of it. Pattern = A repeated way that something is done. For example, if you drew a square then a triangle and repeated doing so, it would be a pattern. Template = A shaped piece of material used as a pattern for processes such as cutting out, shaping, or drilling

sample: 1.A small part or quantity intended to show what the whole is like; 2.A small amount of a food or other commodity, especially one given to a prospective customer; pattern: A repeated decorative design; template: 1.A shaped piece of rigid material used as a pattern for processes such as cutting out, shaping, or drilling. 2.Something that serves as a model for others to copy.