Previously when burials took place with regards to the activities that place at the grave site itself, I recall the following: There were no sheets or

Question

Previously when burials took place with regards to the activities that place at the grave site itself, I recall the following: There were no sheets or cloths used to cover the planks. Previously, we used to mix mud and stones and use that to seal and fill the gaps, we also used tree leaves and sometimes mixed it with the mud to fill gaps. Today, a white sheet is placed and used to throw over the planks and to squeeze between the gaps. Is this correct? Please can our respected Ulama advise.