Thanks for posting in the Community, @anisachkar77.
Right now, the option to assemble items is unavailable in QuickBooks Desktop (QBDT) Pro. But I've got two alternative methods you can perform to achieve your goal.
First, I recommend looking for a third-party app that can integrate with your Pro version. This way, you'll be able to build assemblies using your products in the program. I'll guide you how.
The screenshot below shows you the second to sixth steps.
Second, I'd suggest upgrading your company file to another edition. You can choose either Premier, Enterprise, or Accountant.
Once done, you'll have to turn on the inventory tracking feature in the preferences. Then, set up your product's components and add their bill of materials. That way, you can start assembling your items in the software. For more details, see Steps 1 - 4 through this article: Track The Products You Manufacture. This link is specific to the US region, but it also applies to your country.
You can always run and customise any item reports in QBDT. These will help you review your inventory statuses and their pending builds. For more details, visit this article: Customising Item Reports.
I'm here anytime you have other concerns. Keep safe always, @anisachkar77.
Consider upgrading to QB Premier with a one time license to have the assembly feature. For 1 user, you may purchase the license for $500 directly, or less than $400 thru a partner/reseller.