How can I see what is stored in my depot? The max of making stimpacks for example is 15, do the others go to my depot?

Thanks in advance

When you look at your storage you will see it in the upper right corner. Where it actually really goes is irrelevant. It's bassed on your Medbay or Science Room capacity. So if you have a double wide Medbay or Science Room that gives you 20 storage then you can have 25 Stim Packs and 25 Radaway. If you have a Dowble wide Science Room and a Single Medical Bay then you could have 25 and 15. The storge room itself is seperate and applies to Weapons and Outfits.

I still can't find it. What kind of stuff you can in the depot? Food etc?

Are you referring to your weapons and uniforms?

I updated http://www.gamesas.com/topic/1521786-enhanced-vault-dwellers-survival-guide/ to show a little more information about the Storage room. It should answer your questions. Check the section on Vault Storage.