how to build project from cmakefiles ?

[wibble]

Sir,
can you suggest simple OS for pine time, easy to program and easy to do customization. if you can share the links and references will be grateful to you.

Wasp-os is probably the easiest and best documented in general at the moment. That page has links to the related documentation. Having said that, depending on your background and experience, and possibly whether you're a Windows, Mac or Linux user, you may find one of the others easier if less well documented. Most of them are listed in the wiki. @lupyuen has a series of Medium posts that are worth reading too, and include use of VSCode for programming and debugging the PineTime from any of Windows, Mac and Linux as well as using the Raspberry Pi as the programming and debugging interface.