Windows service running multiple processes using tasks

I have a C# Windows Service that has a Timer that checks every 10 seconds a "flag" in my SQL Table for any Process Pending To Execute.

So right now I have inside my Windows Service:

private void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e) {

    // flag so the process is only executed one at a time.
    if (!_isProcessBusy) {

        RunProcess();

    }
}

private void RunProcessSync() {

    _isProcessBusy = true;

    // ... here all the code for doing the internal process ...

    // when process is Done then change the flag so a new process can be executed
    _isProcessBusy = false;

}

Now I need to let the Windows Service Runs multiple threads of the same process, So if in my SQL Table I have 3 processed to execute then I will let the service run the 3 at the same time.

I was thinking to use System.Threading.Tasks library but don't know if this is the right approach or maybe there is something easier.

There isn't really a question here but:

Yes. You can use Tasks, and async-await, and Parallel. The simplest option here would probably be to use Parallel.Invoke:

Parallel.Invoke(new Action[]
{
    () => RunProcess(1),
    () => RunProcess(2),
    () => RunProcess(3)
});

This will internally use the TaskParallelLibrary, but it's much simpler. more here: Parallel.Invoke() vs. Explicit Task Management