Hi,
TestComplete is extremely well documented and it is really worth to read its documentation for details.
First off, you may try record a simple keyword test (which is suggested by default) to get an initial impression. (Don't expect the recorded test to be reliably replayed. Reliable replay of the recorded test requires some preliminary NameMapping activities.)
https://support.smartbear.com/testcomplete/docs/testing-with/creating/index.html
Then you may convert recorded keyword test to code (right click it and select appropriate command from the context menu) to get a coded version of recorded test.
https://support.smartbear.com/testcomplete/docs/testing-with/running/index.html
Before going on, I would recommend to carefully read documentation about how TestComplete recognizes and addresses objects of the tested application: https://support.smartbear.com/testcomplete/docs/testing-with/object-identification/index.html
Last but not the least: Page Object Model and search by XPath are holy cows in Selenium world. But they are not the best means for TestComplete tests. Actually, Object Browser already provides you with a kind of POM, so no real need to re-implement it. And the search methods provided by TestComplete (Aliases and .FindXXX() methods) work faster and are more convenient and flexible then search by XPath (which you will not be able to use for Desktop anyway ;) )
Also, recordings from the https://support.smartbear.com/screencasts/testcomplete/ page are worth to be seen.
