Milad,
In one project, it took me 2 hours to create an Excel risk register by incorporating the 20 or so risk characteristics from the PMBoK Guide ed6. The register has three sections: identification, assessment, and response planning.
We (the team) checked it in our weekly status meetings, asking ourselves whether we have new information about existing risks and whether we see emerging risks. The risk owner does the main work on a specific risk. High risks were discussed with the client, and he should also take the roles of risk owner or response owner, if appropriate.
Don't do all the work yourself.