Please note that if you have a campaign running for an app in some country then you can't run another campaign for the same app in the same country. If you try to run multiple campaigns for the same app in the same country then only one will be active at a time but rest will be in a waiting queue.
In another words, we can have only one active campaign for same app in a particular country at a time i.e we can NOT run multiple campaigns for same app in a particular country as such but there is a tweak to solve this problem as given below.
If you want to run multiple campaigns for same app, same country then what you can do is;
While creating campaign choose "Burst" as your delivery type and apply some capping such as 250 installs per day. Do the same with few more campaigns. Due to burst mode what will happen is the campaign will reach it's daily cap ASAP and go into "Waiting" status then another campaign will become "Active" and after some time that campaign may also reach it's cap then similarly next campaign would become active and so on...
Bonus. Sketch is small bonus that has some of the theme. Front's Sketch file comes with all demo pages design only. Front is not only for developers but also for designers.