Go to the Development Goals & OKRs section. 
Click the "New goal" button to set the Development Goal.
A window that appears allows you to set the goal with template or suggests to create " + New template".

Let's take a look how to set the New goal. After you click on " + New template", you will be taken to the Goal creation page. Enter its name, and if necessary, add a description.
Set a deadline for the goal.
Choose an employee or assign the goal to yourself.
Select the skill matrix, where you will create Development plan. In case you have only one skill matrix, it'll be selected automatically.

Click on "+" in Focus skills tab.

Choose the skill matrix you need.
Add skills.  And click to "Save" button.
To achieve goals - break them into tasks. You can simply write them - click on "+" and add a checklist of tasks you need to to or (add material from knowledge base).
After setting goals to the skills, save the goal for development.