How to pass parameter to asset from op in dagster

Question

I am new to dagster and having difficult in running the asset for different parameter values when job scheduled.

I have created a pipeline using dagster.

Trying to materialize the outcome of upstream asset multiple_num() and using op to pass parameter value to the asset.

simplified example is

@asset
def get_a():
    return a
    
@asset 
def get_b():
    return b
    
@asset
def multiple_num(get_a, get_b):
    return c
    
@op
def get_values():
    values = ['a','s','e']
    for value in values:
        yield RunRequest(
            run_key=None,
            asset_selection = [AssetKey(multiple_num)]
        )
        cleanup_directory(value)

def cleanup_directory(): -> str
    return status
    
@job
def run_values():
   get_values()

Have to call the asset for different parameters values when job scheduled?