To do list?

You collect uranium from stewies quests and then buy mystery boxes that have items for the to do list area.

The To Do List is a list of all quests that you need more items in order to complete and collect the prize specified for that item. Once you collect all items needed for a particular quest, (usually 3 items needed for each) & you go ahead and CRAFT the item and collect your prizes for that item the it will go over to the DONE list. In the DONE list you can watch clips of the FG story line but not a lot else to do. As far as I can tell you can only collect each item & associated bonuses once.

It is not to clear what items you need to get from mystery boxes, but don't worry about that as you have no control over what is inside a mystery box, as you collect more bonuses you will find there are quite a number of duplicate items in mystery boxes but they are not wasted as for 10 duplicates you get an extra box that might just have that 1 item needed. You don't need any uranium to collect the box you just click the collect button when it is available, but be warned if you get to the 10 duplicate items to get extra box and you collect more that 10 items that are also duplicate they are not carried over and duplicates will not count until you collect the available box so if possible collect the box as soon as you get to 10 duplicates.

If you want to see what bonuses are given with each quest go to the TO DO LIST by clicking the backpack button and in the bottom right corner which is usually a TV, T-shirt or a box with a keyhole and it flips the quest over and reveals what you will get for collecting the 3 items needed to craft the item. Clicking the arrow that has replace the tv etc will return you to the image that tells you what you need to get from boxes. Quite a high percentage will get you 1 -3 hours of infinitive lives or a specific number of lives plus other bonuses used in the levels as power ups.