Apps:picsart and phonto and polarr
Step 1:go to picsart
Step 2:Go to collage and click on grid
Step 3:Choose one collage from square
Step 4:add black images to the squares
(yes you'll have to save a black picture just to add the. To the boxes.)
Step 5:It should look like this.....just without the watercolor pic but you can add one if you'd like to.
Step 6:
Save it and go to draw and put in 512x800.
Step 7:place it at the top.
Step 8:Save it then edit it and add any picture you like. You'll need about two.Add it to the black squares and set it on screen.after you add it erase the excess.
Step 9: after you add your two pics(using the same step) add a filter (on polarr) if you want then add text.it should look like this
Show me your covers!