After my last mistakes have been managed, I was able to go on building the base cupboards of the twin kitchen hutches.
It is very satisfying to realize that any mistake can be solved after few moments or few days thinking about a solution. The most important aspect is thinking about finding a solution, not blaming myself, or anybody else. The real questions are: How can I solve this issue? What can I do now? And not: How come I didn't think of that before?
The base cupboards are now assembled and you can see more details and pictures on my website at this particular page. I also included a tip on how to prevent squeezed out glue, and a way to hold a corner square while assembling.