How to merge code from different projects?

We have several testers work on a website, and everyone records one part alone.So, everyone has a project,and now I want to merge the code from all the project into a test suite collection.I just want to run the test tuite collection in Jenkins.How can I do this?

I know we can use the same project in the begenning ,but we have create several projects before I knew this method.So…how can I solve this problem?thks.

I would just have everyone zip up their project folders, send them all to one machine, then combine projects into one using the file explorer.