How to scan for viruses Avast! Free

I feel like this might be a novice I’ve been using avast for years and never had a problem understanding the program, it was pretty straight forward and simple. Ever since the update I can’t figure out how to work the scans, now you how to select the areas to scan and I don’t know which ones I should pick, do I just pick them all? There used to be an option for a quick scan and one for full system scan, is there a way for me to get those back? I liked doing quick scans weekly and full scans monthly to make sure nothing slips by. Thank you.

Avast FAQ section http://www.avast.com/faq.php