Kitchen cabinet pieces come from the brown chests you get from leveling up and sometimes from the shop. Shop items change daily. (Read other posts in this thread for tips and tricks and in particular the post from geomiah regarding brown chests for a helpful trick!)
Keep merging the cookies and empty jars to find out :). The stacked cooked are used for orders. The empty cookie jars are merged together to make gems. (First they turn into boxes with glass bottles in them, 2, 3, then 4 bottles. Two 4 bottle boxes makes a gem). The gems are then merged together to eventually make gem trees which gives you gems to buy things from the shop or to pay for the “skip” to get more items from something that is recharging. It’s quite a long process for the gem trees, but worth it!
Another tip: on the home screen when you open the game, click the book in the bottom right corner. It’s automatically on the tab for the rooms, but at the top there are different tabs so you can go through and see the max levels of things you’ve made by merging so far. Things you haven’t merged to that level yet will be empty with a little lock icon, indicating that you haven’t merged anything to that level yet. But it helps to give you an idea of just how many things you can merge and what you need to keep merging to make other items.
Comment found on Mergedom: Home Design: How to get kitchen cabinet...
What do you do after you merge all the empty jars and the crate is at max level? What do you merge that with to get the gem tree?
Comment found on Mergedom: Home Design: Tree gems
Combine empty jars and you will eventually get a gem tree.
Comment found on Mergedom: Home Design: How do I use max...