or you can do like this
Moving files to the Virus Chest https://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=501#idt_03
Submitting files from the Virus Chest to avast! Virus Lab https://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=501#idt_07