If you are male and at a dinner party, be a class act and follow this traditional point of etiquette: Remain standing in the dining area until the hostess takes her seat. While standing, if the woman or girl who will be seated to your right happens to comes to the table, you are correct in pulling out her chair and helping to seat her.
Unlike the men, women do no need to wait for the hostess to sit. But both sexes wait for the hostess to take her napkin and fold it in her lap before they do.
By the way, since not all men are familiar with this point of etiquette, don’t be surprised if you are one of the few, or the only one, standing. And don’t feel self conscious in the least about doing so.