You go to ana-white.com and look at her playhouse plans ... they are awesome.

Ana White is good. Here are a bunch of (mostly) free plans. Browse if only to get ideas. http://free-woodworking-stuff.com/docs/plans/childrens-playhouse-plans.htm and http://www.woodworkersworkshop.com/resources/index.php?search=playhouse

You should also look at the snap or screw together plastic yard sheds if you don't want to get into a bunch of carpentry, painting, roofing, door and window fitting, etc. You can put one together in an afternoon.

Check out the plans at https://paulsplayhouses.com/ for both free and for sale. There are quite a few to choose from

Cecilia-

Good advice given already. I am guessing that, if you are asking this question, you probably don't have the skills and the power tools needed to easily produce something you will be happy with. I'm not trying to insult you, but just wanted you to know that things that may look simple in a plan may require more skill than you currently have. I've been doing woodworking for over 50 years, and remember well my first projects when I didn't have much skill, or many of the right tools, and it was not fun, and did not reflect the effort I put in to them. I'm all for people acquiring construction skills; just don't bite off more than you can chew with this one.