Pin tabs in collections so that when you open them, your important or frequent tabs can be pinned.
Pinning a tab means that it is minimized and "pinned" to the left most side of your browser window - it will stay there so that it is easily accessible.
You can now pin (and unpin) tabs in a collection to control their state upon opening up the collection. Simply click on the tab menu within a collection and select "Pin tab". Afterwords, when you open up that collection those tabs will be pinned.