[Haskell-beginners] Parsec and Parsing

Hi, I have two types, Tag = String Val = String and I want to creat expressions based on equality,  t = v  (where t is Tag, v is Val) and containment ie t IN v1, v2, v3, v4 ie a tag equals a value or a tag is contained in a list of values. Furthyermore I would like to apply AND and OR, i.e. (t1 = v OR t1 IN v1, v2, v3) AND (t2 = v2) ect etc I want to use Parsec and I'm ok with basic combinators but I want to get as far as making this a simple DSL but I don't want to use buildExpressionParser  - at least not initially. I want to do this from first principles, understand what I'm doing and then maybe use buildExpressionParser. Any help would be really appreciated. Thanks Mike